Formaldehyde and Other Aldehydes

Formaldehyde

and Other Aldehydes

Committee on Aldehydes

Board on Toxicology and Environmental Health Hazards

Assembly of Life Sciences

National Research Council

NATIONAL ACADEMY PRESS
Washington, DC 1981

FY

NOTICE: The project that is the subject of this report was approved
by the Governing Board of the National Research Council, whose members
are drawn from the councils of the National Academy of Sciences, the
National Academy of Engineering, and the Institute of Medicine. The
members of the Committee responsible for the report were chosen for
their special competences and with regard for appropriate balance .

This report has been reviewed by a group other than the authors
according to procedures approved by a Report Review Committee
consisting of members of the National Academy of Sciences, the
National Academy of Engineering, and the Institute of Medicine.

The National Research Council was established by the National
Academy of Sciences in 1916 to associate the broad community of
science and technology with the Academy's purposes of furthering
knowledge and of advising the federal government. The Council
operates in accordance with general policies determined by the Academy
under the authority of its congressional charter of 1863, which
establishes the Academy as a private, nonprofit, self-governing
membership corporation. The Council has become the principal
operating agency of both the National Academy of Sciences and the
National Academy of Engineering in the conduct of their services to
the government, the public, and the scientific and engineering
communities. It is administered jointly by both Academies and the
Institute of Medicine. The National Academy of Engineering and the
Institute of Medicine were established in 1964 and 1970, respectively,
under the charter of the National Academy of Sciences.

The work on which this publication is based was performed pursuant
to Contract 68-01-4655 with the Office of Research and Development of
the Environmental Protection Agency (Dr. Alan P. Carlin, Project
Officer) .

Library of Congress Catalog Card Number 81-81738
International Standard Book Number 0-309-03146-X

Available from:

NATIONAL ACADEMY PRESS

2101 Constitution Ave., N.W.

Washington, D.C. 20418

t_ ,?

^

* Printed in the United States of America

V

COMMITTEE ON ALDEHYDES

JACK G. CALVERT, Ohio State University, Columbus, Ohio, Chairman
LYLE F. ALBRIGHT, Purdue University, West Lafayette, Indiana
EILEEN BRENNAN, Cook College, New Brunswick, New Jersey

STUART M. BROOKS, University of Cincinnati School of Medicine,
Cincinnati, Ohio

CRAIG D. HOLLOWELL, University of California, Berkeley, California
DAVID H. W. LIU,* Woodward-Clyde Consultants, San Francisco, California

CHARLES F. REINHARDT, Haskell Laboratory, E. I. du Pont de Nemours &
Company, Wilmington, Delaware

JAMES A. FRAZIER, National Research Council, Washington, D.C., Staff
Officer

NORMAN GROSSBLATT, National Research Council, Washington, D.C., Editor

LESLYE B. GIESE, National Research Council, Washington, D.C., Research
Assistant

JEAN E. PERRIN, National Research Council, Washington, D.C., Secretary

*Early in the preparation of this report, Dr. Liu was with SRI
International, Menlo Park, California.

111

BOARD ON TOXICOLOGY AND ENVIRONMENTAL HEALTH HAZARDS

RONALD W. ESTABROOK, University of Texas Medical School, Dallas,
Texas, Chairman

THEODORE CAIRNS, Greenville, Delaware

VICTOR COHN, George Washington University Medical Center, Washington,
D.C.

JOHN W. DRAKE, National Institute of Environmental Health Sciences,
Research Triangle Park, North Carolina

A. MYRICK FREEMAN, Bowdoin College, Brunswick, Maine
RICHARD HALL, McCormick & Company, Hunt Valley, Maryland

RONALD W. HART, National Center for Toxicological Research, Jefferson,
Arkansas

PHILIP LANDRIGAN, National Institute of Occupational Safety and
Health, Cincinnati, Ohio

MICHAEL LIEBERMAN, Washington University School of Medicine, St.
Louis, Missouri

BRIAN MacMAHON, Harvard School of Public Health, Boston, Massachusetts
RICHARD MERRILL, University of Virginia, Charlottesville, Virginia
ROBERT A. NEAL, Vanderbilt University, Nashville, Tennessee
IAN NISBET, Massachusetts Audubon Society, Lincoln, Massachusetts
CHARLES R. SCHUSTER, JR., University of Chicago, Chicago, Illinois

GERALD WOGAN, Massachusetts Institute of Technology, Cambridge,
Massachusetts

ROBERT G. TARDIFF, National Research Council, Washington, D.C.,
Executive Director

IV

ACKNOWLEDGMENTS

This document is the result of individual and coordinated efforts
by the members of the Committee on Aldehydes. Although, as detailed
below, individual members were responsible for specific sections, the
entire report was reviewed by the full Committee. The summary
(Chapter 2) and the recommendations (Chapter 3) represent a consensus
of the Committee members.

The introduction (Chapter 1) was prepared by the Chairman, Dr.
Jack G. Calvert. Chapter 4, on the properties, production, and uses
of the aldehydes, was prepared by Dr. Lyle F. Albright, Dr. Calvert,
and staff; the Appendix, which contains details on many specific
aldehydes, was prepared by staff. Chapter 5, on sources and
concentrations, was a joint effort of Dr. Calvert, Dr. Albright, Dr.
Eileen Brennan, Dr. Craig D. Hollowell, and Dr. David H. W. Liu,
assisted by Dr. William R. Mabey. Chapter 6, on measurement methods,
was written by Dr. Hollowell, assisted by his associate. Dr. Robert R.
Miksch, and by Dr. Brennan and Dr. Liu. Dr. Stuart M. Brooks and Dr.
Charles F. Reinhardt prepared Chapter 7, on health effects of
formaldehyde, and Chapter 8, on health effects of some other
aldehydes, with the assistance of Dr. Francis N. Marzulli, Mr. Richard
C. Graham, and Dr. Joel Bender. Chapter 9, on the effects of
aldehydes on vegetation, was written by Dr. Brennan, and Chapter 10,
on the effects on aquatic organisms, was written by Dr. Liu.

We acknowledge the contributions of Dr. Robert Frank, who served
as chairman of the Committee in its formative period.

Special recognition should be given to Dr. Albright, who chaired a
subcommittee meeting at which resource information was presented by
industrial representatives of the Formaldehyde Institute, the American
Textile Manufacturers, Inc., the Manufactured Housing Institute, the
Hardwood Plywood Manufacturers Association, and Aerolite SPE Corp.
Special thanks should also be extended to Dr. Brooks, who chaired a
subcommittee on the health effects of formaldehyde, which included Dr.
Donald Proctor and Dr. Edward Emmett of Johns Hopkins University, who
assisted in the evaluation of the health effects, and representatives
of the Formaldehyde Institute, who made available resource information
on the health effects. The efforts of Dr. John Clary and Mr. Kip
Hewlett in organizing representation and the presentations made at
these subcommittee meetings are greatly appreciated, as well as those
of Dr. Leon Starr of the Celanese Corporation for his consultation and
information resources furnished to the Committee.

For providing resource material and other information, we express
our gratitude to the following:

v

Dr. Eric R. Allen, Atmospnenc Sciences Research Center,
State University of New York, Albany, New York

Mr. Douglas Anthon, Lawrence-Berkeley Laboratory, University
of California, Berkeley, California

Dr. Charlotte Auerbach, University of Edinburgh, Edinburgh,
Scotland

Mr. W. L. Benning, Manufactured Housing Institute, Arlington,
Virginia

Mr. Charles A. Campbell, Aerolite SPE Corporation, Florence,
Kentucky

Dr. T. Cooke, Textile Research Institute, Princeton, New
Jersey

Mr. Maynard Curry, U.S. Department of Housing and Urban
Development, Washington, D.C.

Dr. John W. Drake, National Institute of Environmental Health
Sciences, Research Triangle Park, North Carolina

Dr. Julius Fabricant, New York State College of Veterinary
Medicine, Ithaca, New York

Ms. Mary Leah Fanning, Lawrence-Berkeley Laboratory,
University of California, Berkeley, California

Mr. Robert B. Faoro, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina

Mr. R. David Flesh, Del Green Associates, Foster City,
California

Dr. Alfred L. Frechette, Massachusetts State Department of
Public Health, Boston, Massachusetts

Dr. A. Myrick Freeman II, Department of Economics, Bowdoin
College, Brunswick, Maine

Mr. Ernest Freeman, Department of Energy, Washington, D.C.

Dr. Thomas E. Graedel, Bell Laboratories, Murray Hill, New
Jersey

Mr. Serge Gratch, Ford Motor Company, Dearborn, Michigan
Mr. William Groah, Hardwood Plywood Manufacturers

Association, Arlington, Virginia

Dr. Daniel Grosjean, Environmental Research and Technology,

Inc., West Lake Village, California

Mr. Jan Heuss, General Motors Research Laboratory, Warren,
Michigan

Mr. Richard C. Holmquist, American Mining Congress,
Washington, D.C.

Dr. Nelson S. irey, Armed Forces Institute of Pathology.
Washington, D.C.

Dr. Howard Johnson, SRI International, Menlo Park, California

Dr. Philip Landrigan, National institute for Occupational
Safety and Health, Cincinnati, Ohio P^ionai

Dr. Charlotte R. Lindley, Department of Chemistry, Ohio State
University, Columbus, Ohio

Dr. Gunnar Lundqvist, Arhus University, Arhus, Denmark

VI

Dr. Geoffrey Meadows, E. I. du Pont de Nemours and Company,
Wilmington, Delaware

Mr. Andrew Micula, New Jersey Department of Environment
Protection, Trenton, New Jersey

Dr. Dominick J. Mormile, Consolidated Edison, New York, New
York

Mr. Charles Morschauset, National Particle Board Association,
Silver Spring, Maryland

Dr. Demetrios J. Moschandreas, GEOMET Technologies, Inc.,
Gaithersburg, Maryland

Mr. John F. Murray, Formaldehyde Institute, Scarsdale, New
York

Ms. Laura A. Oatman, Minnesota Department of Health,
Minneapolis, Minnesota

Mr. Edward Owens, Aberdeen Proving Grounds, Maryland

Mr. James Paine, Texas Air Control Board, Austin, Texas

Dr. G. J. Piet, National Institute for Water Supply,
Voorburg, The Netherlands

Dr. James M. Ramey, Celanese Corporation, New York, New York

Dr. Yuko Sasaki, Tokyo Metropolitan Research Institute for
Environmental Protection, Tokyo, Japan

Dr. Eugene N. Skiest, Borden, Inc., Columbus, Ohio

Dr. Ronald J. Spanggord, SRI International, Menlo Park,
California

Dr. Karl J. Springer, Southwest Research Institute,
San Antonio, Texas

Dr. Edgar R. Stevens, California Statewide Air Pollution
Research Center, Riverside, California

Mr. William Stockwell, Department of Chemistry, Ohio State
University, Columbus, Ohio

Mr. John G. Tritsch, American Textile Manufacturers
Institute, Washington, D.C.

Dr. Michael P. Walsh, U.S. Environmental Protection Agency,

Washington, D.C.

Mr. Frank Walter, Manufactured Housing Institute,
Arlington, Virginia

Mr. Ralph C. Wands, Mitre Corporation, McLean, Virginia

Dr. Jonas Weiss, CIBA-GEIGY Corporation, Ardsley, New York

Dr. Rather me W. Wilson, Pacific Environmental Services,
Santa Monica, California

Ms. Mary Ann Woodbury, Wisconsin State Department of Health
and Social Services, Madison, Wisconsin

Free use was made of the resources of the Toxicology Information
Center of the Board on Toxicology and Environmental Health Hazards,
National Research Council; the National Library of Medicine; the
National Agricultural Library; the Library of Congress; and the Air
Pollution Technical Information Center of the Environmental Protection
Agency. Also acknowledged is the assistance given to the Committee by
the National Academy of Sciences Library and various other units of
the National Research Council.

VI 1

CONTENTS

1 Introduction 1

2 Summary 3

3 Recommendations 11

4 Commercial Production, Properties, and Uses of

the Aldehydes 20

5 Aldehyde Concentrations, Emission, and Environmental
Generation and Transformation Reactions 36

6 Analytical Methods for the Determination of

Aldehydes 132

7 Health Effects of Formaldehyde 175

8 Health Effects of Some Other Aldehydes 221

9 Effects of Aldehydes on Vegetation 256

10 Effects of Aldehydes on Aquatic Organisms 276
Appendix: Properties, Uses, and Synonyms of Selected Aldehydes 289

ix

CHAPTER 1
INTRODUCTION

This report was prepared at the request of the Environmental
Protection Agency (EPA) by the Committee on Aldehydes, which was
appointed by the National Research Council in the Board on Toxicology
and Environmental Health Hazards, Assembly of Life Sciences. The
Clean Air Act requires that from time to time the Administrator of EPA
evaluate the need for air-quality criteria on pollutants that may have
adverse effects on man or the environment. This report is to be used
by EPA in assessing the need for such criteria on some of the
aldehydes. It is intended to identify and characterize the more
important aldehydes that pollute the environment, the sources of their
emission, their concentrations, their transformation and transport,
their effects on the health of animals and humans, and their effects
on the aquatic and terrestrial environments. It is not intended to
recommend concentrations of polluting aldehydes for use in developing
regulations, but rather to evaluate the available data for EPA to use
in judging the need for regulatory strategies to control aldehyde
pollution. It is hoped that wide dissemination of this report will
inform physicians and other health professionals about the health
effects of aldehydes and how they may be encountered at hazardous
concentrations in the environment.

The Committee had hoped to address the economics of the options
for abatement of aldehyde pollution, and it chose formaldehyde as the
model of the aldehydes because of its perceived importance and because
it is used in a wide variety of products. Techniques for abating
formaldehyde emission are still evolving and being tested; their value
has not been proved, and their costs and cost-benefit relationships
are not known. Therefore, on the grounds of a lack of usable
information, the economic analysis of control options was abandoned.

Chapters 2 and 3 summarize the Committee's findings and set forth
the Committee's recommendations, respectively.

Chapter 4 describes commercial methods of production of the
aldehydes and their uses. Chapter 5 reviews the reported atmospheric
concentrations of the aldehydes in clean and urban environments, in
indoor environments, and in surface and drinking waters; considers the
sources of direct emission from industrial operation, combustion,
consumer products, natural vegetation, and indoor environments; and
evaluates current theories of the mechanism of aldehyde generation in
the atmosphere, the aldehyde removal processes that operate in the

environment, and the secondary effects of aldehydes in the chemistry
of the polluted atmosphere. Chapter 6 reviews and evaluates the
methods of analysis of formaldehyde and selected higher aldehydes and
methods of sampling and of preparing standards.

Formaldehyde has prominence throughout the report, because it is
ubiquitous, is used in very large quantities, and is mutagenic in
microorganisms and insects and carcinogenic in Fischer 344 rats, in
Chapter 7, the health effects of formaldehyde in terrestrial animals
and humans are discussed in detail; Chapter 8 covers the health
effects of selected other aldehydes; Chapter 9 discusses the effects
of selected aldehydes on vegetation; and Chapter 10 discusses the
effects of some aldehydes on aquatic organisms.

The Appendix summarizes in tabular form several of the important
physical and chemical properties of a number of the aldehydes that
have been found in the environment. This compilation is not intended
to be exhaustive, nor should the importance of these aldehydes be
inferred from their listing.

This report cites references available to the Committee up to July
1, 1980, with one exception: a study that was made public in November
1980 and provided more recent information on an earlier study that was
cited. The work of the Committee from July 1, 1980, onward was
devoted to an analysis of the information in hand. Thus, scientific
papers and analyses published after that date were not considered.

CHAPTER 2
SUMMARY

Although many of the aldehydes are minor components of the natural
environment, we now recognize the potential impact of some of them on
the urban and indoor environments. Thus, there is a need to study
their sources r concentrations, transport, and transformations and
their effects on various environmental and biologic systems.

PRODUCTION, USES, AND PROPERTIES OF THE ALDEHYDES

The aldehydes are produced at the rate of several billion pounds
per year in the United States. Formaldehyde is the most important
aldehyde produced commercially; about 9 billion pounds per year of the
37-50% aqueous solution, called formalin, are prepared. The
production methods depend on the catalytic oxidation of methanol .
About half the formaldehyde produced is used in the preparation of
urea-formaldehyde and phenol-formaldehyde resins, which are applied in
the manufacture of plywood, particleboard, foam insulation, etc.
Another 25% is used to make other high polymers and resins. Its use
is so diversified that there is a potential for exposure in a number
of occupational, environmental, and consumer settings. About 1
billion pounds of acetaldehyde are prepared commercially each year in
the United States, about 80% of it by the catalytic oxidation of
ethylene in aqueous solution. This aldehyde is the major raw material
for the preparation of acetic acid and other important chemicals.
Smaller amounts of acrolein and the higher-molecular-weight aldehydes
are prepared commercially. The simplest aldehydes are volatile
compounds with characteristic pungent odors. These compounds are
readily oxidized and polymerized.

ALDEHYDE EMISSION, CONCENTRATIONS, AND ATMOSPHERIC TRANSFORMATIONS

The aldehydes are introduced into the atmosphere through a variety
of natural processes and as a result of human activity. In the
atmosphere, they are generated through the photooxidation of both
naturally occurring and anthropogenic hydrocarbons. They are injected
directly into the atmosphere in the exhaust gases from automobiles and
nther equipment in which hydrocarbon fuels are incompletely burned.

Aldehydes are emitted from various industrial and manufacturing
operations, power plants that burn fossil fuels, forest fires and open
burning of wastes, and vegetation.

The accumulation of aldehydes in the atmosphere as a result of
their direct release and photochemical generation is counterbalanced
by several important removal paths. The aldehydes absorb the
ultraviolet component of sunlight and decay into free-radical and
molecular products. They also react rapidly with the highly reactive
free radicals, largely the hydroxy free radical, present in the
sunlight-irradiated atmosphere. Because of the high water solubility
of formaldehyde and the other low-molecular-weight aldehydes, one
expects the efficient transfer of aldehydes into rainwater, the
oceans, and other surface waters. The high reactivity of the
aldehydes leads to rather short half-lives, of around a few hours, in
the sunlight-irradiated lower atmosphere. Thus, the atmospheric
transport of the aldehydes over long distances is probably a less
likely source in remote areas than their local generation from
transported, longer-lived precursors, such as the less reactive
hydrocarbons. The lifetime of formaldehyde in aqueous media may be
somewhat greater than that of the gas-phase species, because the
hydrated form of formaldehyde, which dominates in these conditions,
does not absorb sunlight appreciably. The higher aldehydes do not
have this protective mechanism, because of the lower degree of
hydration. Microorganisms appear to play an important role in the
degradation process, which may take 30-72 h in these cases (in natural
conditions) .

Many people may be exposed to aldehydes at high concentrations
(i.e., above ambient) in the indoor environment of the home. Sources
of aldehydes in conventional residential buildings and mobile homes
include building materials, insulation, combustion appliances, tobacco
smoke, and various consumer products. These sources emit aldehydes in
substantial amounts; as a result, indoor aldehyde concentrations
almost always exceed outdoor concentrations.

In any environment, the ambient concentrations of aldehydes depend
on the rates of the formation and removal reactions. In a clean
environment, aldehyde concentrations at ground level are commonly
0.0005-0.002 ppm (0.6-2.5 pg/m 3 ) . In ambient urban air, the
concentrations are much higher, usually an hourly average of
0.004-0.05 ppm (5-61 pg/nr*) during the daylight hours.
Formaldehyde is the dominant aldehyde present, usually constituting
30-75% of the total aldehydes. Acetaldehyde may be present at about
60% of the formaldehyde concentration, with smaller amounts of the
higher aliphatic aldehydes. Acrolein may be present at 10-25% of the
formaldehyde concentration, and the aromatic aldehydes usually make up
only a few percent of the total aldehydes . In most indoor
environments, 24-h average formaldehyde concentrations of 0.05-0.2 ppm
(61-246 yg/nr) are not uncommon today. However, in some indoor
environments concentrations of a few parts per million or higher have
been reported. In the aquatic environment, aldehyde concentrations
are generally less than 1 ppb. Concentrations of some aldehydes in
the parts-per-million range have been reported in industrial effluents,

The aldehydes affect the chemistry of the chemically polluted
atmosphere in a variety of complex ways. An increased aldehyde
concentration decreases the induction period for the generation of the
products of photochemical smog and increases the maximal concentration
of ozone. The aldehydes other than formaldehyde are precursors of an
important class of secondary pollutants, the peroxyacylnitrates and
peroxybenzoylnitrates, which have been identified as highly active eye
irritants and plant-damaging agents. Through several atmospheric
reaction pathways, formaldehyde may be converted to formic acid. The
interaction of formaldehyde and hydrogen chloride can lead to
chloromethylethers, which are potential carcinogens, although current
knowledge (which may be incomplete) indicates that the concentrations
formed in the atmosphere at ambient concentrations of reactants would
be so low that there is little probability of an impact on health.
Thus, formaldehyde affects the quality of the ambient air not only
directly, but also indirectly by way of its chemical transformations,
involvement in photochemical smog reactions, and interaction in
combination with other pollutants.

ANALYTICAL METHODS FOR THE DETERMINATION OF THE ALDEHYDES

The techniques for quantitative analysis of the aldehydes have not
been investigated adequately with respect to the necessary
reliability, sensitivity, and specificity. Accurate analysis for the
aldehydes in the environment is essential to an assessment of their
qualitative and quantitative influence on the environment and on the
health of those exposed. The solution-phase spectrophotometnc
methods are the most commonly used analytical techniques. Although
the individual aldehydes can be selectively measured with methods now
available, the methods require improvement and standardization.
Measurements of "total" aldehyde provide little help in the assessment
of the impact of these compounds in the environment, because the
variation in toxicity among the individual aldehydes is large for
example, the current Occupational Safety and Health Administration
standards for exposure to acetaldehyde, formaldehyde, and acrolein are
200, 3, and 0.1 ppm, respectively. It is recognized that future
analytical methods for aldehydes should provide an accurate
determination of the specific aldehydes present in a given sample.
Several methods appear to offer this potential. Many involve the
derivatization of the aldehydes and the use of gas- or
liquid-chromatographic separations and analysis. Further development
is necessary to establish these methods for general use.

HEALTH EFFECTS OF FORMALDEHYDE

Formaldehyde has been the subject of numerous complaints regarding
irritation of the eyes and respiratory tract, nausea, headache,
tiredness, and thirst. These symptoms have been reported mainly by
residents of homes in which formaldehyde has been identified as a

result of off-gassing from urea-formaldehyde foam insulation,
particleboard, or plywood. Studies of employees exposed to
formaldehyde in the workplace and in controlled exposures have further
indicated that the skin, eyes, and respiratory tract are the target
organs affected.

Aqueous solutions of formaldehyde are damaging to the eye and
irritating to the skin on direct contact. Repeated exposure to dilute
solutions may lead to allergic contact dermatitis. There are some
documented cases showing that formaldehyde is a cause of skin
responses in sensitized persons using cosmetic formulations that
contain formaldehyde at very low concentrations (0.01%). There are
few documented cases showing that formaldehyde is a cause of
hypersensitivity in persons with bronchial asthma; more commonly,
asthma is aggravated by the irritating properties of formaldehyde.
Systemic poisoning from ingestion is uncommon, because the irritancy
of formaldehyde makes ingestion unlikely.

Numerous studies have shown that formaldehyde is irritating to the
eyes and upper respiratory tract of laboratory animals. Preliminary
results of a chronic-inhalation study sponsored by the Chemical
Industry Institute of Toxicology (CUT) have shown that formaldehyde
induces nasal cancer in Fischer 344 rats exposed at 15 ppm 6 h/d, 5
d/wk for 18 mo, but not yet in B6C3F1 mice similarly exposed.
(However, the CUT reported at the Formaldehyde Symposium on November
20-21, 1980, in Raleigh, N.C., that nasal cancer had been observed in
rats exposed at 6 ppm for 24 mo and in mice exposed at 15 ppm for 24
mo.) Fischer 344 rats have also shown dose-related histologic changes
(epithelial dysplasia and squamous metaplasia) of the nasal mucosa
after exposure at 2, 6, and 15 ppm. Although there is no evidence of
the carcinogenicity of formaldehyde in humans, the results of these
studies showing carcinogenicity in rats require that serious attention
be given to an evaluation of the carcinogenic potential of
formaldehyde in exposed humans. Formaldehyde has not altered
reproduction or shown evidence of teratogenicity in animals, but it
has exhibited mutagenic activity in several nonmammalian animal or
cell systems. The human mutagenic and teratogenic potential of
formaldehyde is not known.

The presence of environmental agents other than formaldehyde,
smoking history, variability of health status, age, and genetic
predisposition may modify responses to formaldehyde. These factors
have not been adequately evaluated; that makes it difficult to assess
accurately the health risks attributable solely to formaldehyde.
However, the complaints of residents of homes with formaldehyde-
containing products have been shown to be similar to complaints made
by persons studied in the laboratory at similar formaldehyde
concentrations; hence, these subjective complaints about health
effects may be related to formaldehyde exposure in the home, although
the presence of other pollutants causing the same symptoms must not be
overlooked. Accordingly, a substantial proportion of the U.S.
population may be likely to develop symptoms of irritation, if exposed
to formaldehyde at low concentrations. As discussed in detail in
Chapter 7, on the basis of laboratory tests and various kinds of

population surveys, it nas been estimated that some 10-20% of the
general population may be susceptible to the irritant effects of
formaldehyde at low concentrations. For example, most people report
mild eye, nose, and throat irritation at a concentration of 1 ppm,
whereas some note symptoms at concentrations below 0.5 ppm. In
laboratory investigations, under controlled conditions, responses have
been reported at formaldehyde concentrations as low as 0.01 ppm when
formaldehyde was present in combination with other air pollutants.
Low concentrations may also cause bronchoconstriction and asthmatic
symptoms in some susceptible persons. The specific effects of
continuous exposure on other susceptible populations such as infants,
young children, pregnant women, and the infirm are not known. The
exact numbers of susceptible people residing in environments where
formaldehyde concentrations could produce adverse responses cannot be
determined. Millions of persons live in mobile homes or conventional
homes that have particleboard, plywood, or urea-formaldehyde foam
(resin) insulation. On the basis of monitoring of a fairly large
number of houses in these categories, significant formaldehyde
concentrations were detected in several hundred American homes, and
these concentrations were caused in large part by outgassing from
these building materials. Much of this monitoring was done as a
direct result of customer complaints. Yet other homes in these
categories, including some with customer complaints, demonstrated
formaldehyde concentrations basically comparable with those in homes
that did not contain such building materials. On the basis of
estimates of susceptibility of the general population to formaldehyde,
it may be anticipated that a substantial number of persons are at risk
of adverse health effects (upper and lower respiratory tract effects,
eye irritation, etc.). Because of the incompleteness of the data, no
conclusions can be drawn about the carcinogenic risks to humans
exposed to formaldehyde.

HEALTH EFFECTS OF SOME OTHER ALDEHYDES

The principal effect of human exposure to other aldehydes,
particularly acrolein and acetaldehyde , at low concentrations, is
irritation of the eyes, skin, and mucous membranes of the upper
respiratory tract. It has been demonstrated that several
environmental irritants are ciliotoxic and mucus-coagulating agents.
The aldehydes which include acetaldehyde, propionaldehyde, and
acrolein may thus facilitate the uptake of other atmospheric
contaminants by the bronchial epithelium.

Acetaldehyde, the least toxic of the atmospheric aldehydes, is
slightly toxic when administered orally. The effect of direct contact
with liquid acetaldehyde has not been studied, but industrial
experience suggests that there is little hazard. Repeated-exposure
studies indicated that significant toxic effects appear only at high
concentrations. An 18-wk inhalation study in hamsters showed no
adverse effects at 390 ppm (7.0 x 10 5 yg/m 3 ) . Acetaldehyde is
thought to be an important contributor to the health

effects of cigarette smoke. It does not appear to have substantial
mutagenic or carcinogenic effects, but more extensive studies are
required to test this possibility. A major source of acetaldehyde in
the body is the metabolism of ethanol. Acetaldehyde has shown
embryotoxic and teratogenic effects in mice similar to those produced
by ethanol.

Acrolein is the most acutely toxic of the atmospheric aldehydes.
It is highly toxic by the oral and skin-absorption routes. It
produces severe injury on contact with the skin and eyes. Inhalation
of acrolein vapors by cats and rats produces severe eye and
respiratory tract irritation at concentrations as low as 12 ppm (2.8 x
10 4 yg/m 3 ) and death in rats after 4-h exposure at 8 ppm (1.8 x
10 yg/m ) ; its vapors produced little or no effect at up to 0.2
ppm (458 ym/nr) . Exposed animals appear to develop tolerance
within a few weeks. Higher concentrations cause species- and
dose-dependent histopathologic changes in both the upper and the lower
respiratory tract. Although acrolein has been shown to be mutagenic
in nonmammalian systems, it has not been shown to be carcinogenic in
hamsters. In a single study, it was found not to be embryotoxic in
rats.

Crotonaldehyde produces symptoms similar to those described for
acrolein. Eye and respiratory tract irritation is seen with
propionaldehyde, n-butyraldehyde , isobutyraldehyde, and chloral.
Chloral is unique, in that its inhalation toxicity puts it in the
highly toxic category for acute exposures. Other high-molecular-
weight aldehydes such as chloroacetaldehyde, valeraldehyde, furfural,
the butyr aldehydes , glyoxal, malonaldehyde, benzaldehyde,
synapaldehyde, and the naturally occurring aldehydes appear to be
less toxic than formaldehyde and acrolein, although studies of these
compounds are incomplete.

EFFECTS OF ALDEHYDES ON VEGETATION

Several studies concerning aldehyde phytotoxicity have been
reported. Manifestations of injury include visible symptoms on
foliage and effects on growth, photosynthesis, respiration,
transpiration, seed germination, and pollen-tube elongation. Early
California studies demonstrated that exposure of five smog-sensitive
field crops to formaldehyde vapors (uncontrolled fumigations at 2 ppm,
or 2.5 x 10 yg/m 3 , for 2 h) caused no noticeable effect. Some
doses of acrolein (0.1 ppm, or 229 yg/m 3 , for 9 h) and
trichloroacetaldehyde (0.8 ppm, or 4.8 x 10 3 yg/m 3 , for 4 h)
induced smog-like damage to alfalfa leaves, but higher doses of
acrolein (0.6 ppm, or 1.4 x 10 3 yg/m 3 , for 3 h and 1.2 ppm, or
2.8 x 10 3 yg/m 3 , for 4.5 h) caused injury in spinach, endive,
and beet leaves unlike that caused by smog. Visible injury in pinto
bean leaves occurred after 70 mm of exposure to acrolein at 2.0 ppm
(4.6 x 10 3 yg/m 3 ). Products of the irradiated aldehydes in air
have also been tested, in a 4-h exposure at 0.5 ppm. Irradiated
formaldehyde and acetaldehyde caused no damage

to petunias and pinto beans, but propionaldehyde and butyraldehyae
caused a glazing of the lower leaf surface of both plants.

Slightly reduced rates of photosynthesis and respiration were
measured when an alga (Euglena gracilis) was exposed to formaldehyde
at 0.075 ppm (92 yg/m 3 ) for 1 h, and photosynthesis was
significantly reduced after exposure to propionaldehyde at 0.1 ppm
(123 yg/m 3 ) for 1 h. In fasted cells, the effects were minimized.

A rather large concentration (10~^ M, or 24 ppm) of a single
higher aldehyde (trans-2-hexenal, pentanal, hexanal, heptanal,
octanal, or nonanal) decreased the transpiration rate in wheat
seedlings to less than that observed in complete darkness.

Aldehydes have been observed to inhibit pollen-tube elongation in
lily. Although exposure to formaldehyde at 0.37 ppm (454 yg/m 3 )
for 1-2 h had no effect, a 5-h exposure at this concentration resulted
in inhibition. Acrolein was more injurious, causing a 40% decrease in
tube length when the lily was exposed at 0.4 ppm (917 yg/m ) for
2 h.

Various other detrimental effects of aldehydes on plants have been
observed. For example, oat, wheat, corn, barley, tomato, bean,
lettuce, and radish showed a marked reduction in seedling growth and
seed germination after exposure to polymer -treated woods. Presumably,
the formaldehyde vapors that escaped from the wood were responsible.

On the basis of available information, one might expect to find
some response of sensitive plants to aldehydes in ambient air. This
will probably be seen first in the fast-growing herbaceous plants,
rather than the woody, slow-growing species.

Present data suggest that aldehyde phytotoxicity itself is a minor
pollution problem. However, in combination with the more common air
pollutants, nitrogen dioxide and sulfur dioxide, phytotoxicity may be
increased. The aldehydes may also contribute to the generation of the
phytotoxic oxidants ozone and peroxyacyl nitrates, or PAN. Thus, the
vegetation problem could become more serious if aldehyde and other
pollutant concentrations rise substantially.

EFFECTS OF ALDEHYDES ON AQUATIC ORGANISMS

Thirty-six aldehydes have been identified in water, including
industrial and sewage-treatment plant discharges, surface waters, and
drinking water. Although the concentrations of many of these
aldehydes in water are unknown, the concentrations of 22 in natural
bodies of water or in drinking water have been determined to be less
than 0.012 mg/L. The concentrations of five aldehydes that have been
identified in aqueous waste discharges range up to 0.24 mg/L.
Although the water-sampling sites have been limited, they are probably
representative, and the results show that in general the aldehyde
concentrations in the aquatic environment are relatively low.

Only seven of the 36 aldehydes (acrolein, formaldehyde,
acetaldehyde, fur fur aldehyde, crotonaldehyde , propionaldehyde, and
vanillin) have been fully evaluated for acute toxicity in at least two
aquatic species. The lowest reported median lethal concentrations

10

for various exposure times and organisms range from about
0.05 mg/L for acrolein to 112 mg/L for vanillin and 130 mg/L for
propionaldehyde . Acute-toxicity screening tests on 13 aldehydes
showed most to be nontoxic to fish at 5 ppm and all to be nontoxic at
1 ppm. Only acrolein has been evaluated for chronic effects. From
its evaluation of the data, the Environmental Protection Agency has
determined the chronic LC5Q values of acrolein to be 0.024 mg/L for
the cladoceran Daphnia raagna and 0.021 mg/L for the fathead minnow,
Pimephales promelas.

On the basis of the method that uses calculated octanol-water
partition coefficients (P) , most of the aldehydes will probably not
bioaccumulate substantially. However, six of them (capraldehyde,
caprylaldehyde , 3 , 5-di-tert-butyl-4-hydroxybenzaldehyde ,
mesitaldehyde, nonylaldehyde , and undecylaldehyde) have log P values
of at least 3.0; this suggests that they could accumulate appreciably
in the tissues of aquatic organisms in the absence of rapid removal
reactions.

Although little is known about the persistence of aldehydes in
aqueous systems, it appears that a variety of aliphatic and aromatic
aldehydes including formaldehyde, acrolein, benzaldehyde,
salicylaldehyde, syringaldehyde, and vanillin can be biodegraded
relatively rapidly.

The little information available now suggests that aldehydes
(except acrolein) have low to moderate toxicity in aquatic organisms.
We can conclude that the concentrations of aldehydes found in water
are in most cases lower than those shown to have toxic effects in
toxicity tests. There is some evidence that aldehydes do not persist
for long periods in water that contains microorganisms; hence, the
probability of occurrence of long-term effects appears to be low.
However, many of the aldehydes have not yet been evaluated for
toxicity in aquatic organisms, so our conclusion must be regarded as
tentative.

CHAPTER 3
RECOMMENDATIONS

This document reviews the present knowledge on formaldehyde and
some important higher aldehydes with respect to their production,
properties, ambient and indoor concentrations, potential sources and
sinks, and effects on humans, aquatic and terrestrial animals, and
plants. The Committee recognizes that the first priority in its
consideration is the determination of the effects of specific
aldehydes on human health. However, serious deficiencies in its
current knowledge prevent the immediate attainment of this primary
goal. It is necessary to have unambiguous methods of analysis of
specific aldehydes, comprehensive emission inventories, atmospheric
generation and destruction rates, and measured concentrations of the
individual aldehydes in indoor and outdoor environments to which human
populations are exposed, as well as definitive health studies related
to the specific aldehydes. This chapter identifies the missing
scientific information that is needed if sound strategies for the
control or abatement of aldehyde pollution are to be formulated and
offers specific recommendations for obtaining the needed information.
The Committee has not studied the direct or indirect economic impact
of the implementation of these recommendations. The order of
presentation reflects a suggested priority of the needed studies in
each section, although we believe that all the recommendations deserve
serious consideration by those concerned with the effects of the
aldehydes on humans and the environment.

CHEMISTRY OF THE ALDEHYDES IN THE ENVIRONMENT

Many aspects of the sources, sinks, and transformation mechanisms
of the aldehydes in the atmosphere, in outdoor and indoor
environments, on the land, and in the surface waters remain
ill-defined. A variety of further studies are required to permit the
development of useful models of the potential ambient environmental
and indoor concentrations of the aldehydes and their concentrations in
natural surface and ground waters to which humans, terrestrial
animals, aquatic organisms, and plant life will be exposed. Present
information on the aldehyde exposure of the human population is at
best incomplete.

11

12

Tnere are some serious deficiencies in our present knowledge of
indoor aldehyde sources and concentrations. In particular, studies on
the following issues are required, to allow a careful assessment of
the indoor-aldehyde problem: studies of building materials
(particleboard, plywood, urea-formaldhyde foam insulation, etc.) from
the point of view of their aldehyde emission rates and intervening
factors (such as ventilation rate, temperature, and humidity); studies
to measure the emission of other indoor sources of formaldehyde, such
as gas-fired appliances, tobacco smoke, consumer products, and outdoor
air; studies on the type and effectiveness of various schemes to
reduce the indoor concentration of aldehydes; and monitoring studies
that use reliable analytical techniques to assess aldehyde
concentrations in a broad spectrum of occupied indoor environments.

Manufacturers of indoor plywood and particleboard should be able
in the future to produce materials that have substantially lower
emission of formaldehyde; however, it is not clear whether completely
satisfactory solutions to the problem are possible. The Committee
recommends that manufacturers continue work on the following promising
approaches: Somewhat reduced amounts of formaldehyde should be used
in preparation of the resins; improved polymerization recipes and
better control of reaction conditions may result in less unreacted
formaldehyde in the resin product. Techniques should be developed to
remove excess or unreacted formaldehyde from the final product; for
example, controlled heating and extended storage of the product before
sale to the consumer will certainly promote escape of formaldehyde
from the product. The surfaces of the final products should be sealed
to minimize the escape of unreacted formaldehyde to the atmosphere; a
specific sealing agent has recently been reported to reduce
formaldehyde escape by about 70%, and paints and varnishes would
presumably have some similar effect, but information on their use has
not been reported; such sealers may also minimize moisture absorption
and subsequent hydrolysis reactions. If suitable solutions to the
formaldehyde problem of urea- formaldehyde resins cannot be obtained,
the alternative is to select other resins , such as phenol-
formaldehyde, melamine-formaldehyde, or epoxy; it is recognized that
cost, appearance of the final consumer product, and somewhat poorer
physical properties may militate against some or all of these
alternative resins, and other building materials may be required as
replacements for the present types of plywood or particleboard.

The combustion of fossil fuels including natural gas, gasoline,
diesel fuel, oil, and coal and of wood, trash, etc., produces exhaust
gases that contain both aldehydes and unburned hydrocarbons. Unburned
hydrocarbons are transformed in part to aldehydes as intermediate
compounds in atmospheric oxidation reactions. Ambient concentrations
of these compounds in polluted urban areas are increased appreciably
by exhausts from transportation vehicles. The controls used on new
vehicles appear to offer reasonable regulation of both hydrocarbons
and aldehydes. However, careful continued study of the emission from
all internal-combustion engines is required as fuel composition and
engine design are altered in the years ahead. In view of the high
probability of the increased use of gasohol and methanol fuels and the

13

expectation that formaldehyde and acetaldehyde are products of the
incomplete combustion of these fuels, aldehyde emission from the
exhaust of new and old vehicles of all kinds should be monitored
regularly as these fuels increase in use. The aromatic-hydrocarbon
content in liquid fuels, such as gasoline, may be of concern, for at
least two reasons: first, there will be direct emission or
vaporization losses, and, second, these compounds produce aromatic
aldehydes in their atmospheric photooxidation. Benzaldehyde, the
methylbenzaldehydes, and other aromatic aldehydes are precursors of
the highly irritating peroxybenzoylnitrates, which would be formed in
the atmospheric photooxidation reactions expected to occur. Tfte
increasing use of diesel fuels will cause somewhat new emission
control problems. The emission of the higher aldehydes, as well as
the common low-molecular-weight aldehydes, may be expected, and
suitable controls may need to be investigated to address this
potential problem.

The search for synergistic effects involving the aldehydes must
continue. Thus, there should be special research efforts to
investigate the ambient concentrations of bis (chloromethyl) ether in
regions of high formaldehyde and hydrogen chloride concentrations.
Further quantitative work is required to delineate the thermodynamic
and kinetic properties of the formaldehyde-hydrogen chloride-
fa is (chloromethyl) ether system, to allow a quantitative assessment of
the potential formation of the chloromethylether to which human
populations may be commonly exposed.

Outdoor air concentrations of formaldehyde, the higher aliphatic
and aromatic aldehydes, and acrolein should be monitored in the air on
a continuing basis in a large number of heavily populated, rural, and
remote areas, so that a reasonable data base on ambient aldehyde
concentrations can be established.

The expected theoretical relation of the peroxyacylnitrates and
peroxyarylnitrates and ozone to the precursor aldehydes should be
tested in a continuing effort. Ambient concentrations of ozone and
peroxyacetylnitrate and higher homologues should be measured at the
same sampling sites used for the aldehyde determinations. Correlation
checks will require continuous monitoring of nitrogen dioxide, nitric
oxide, nonmethane hydrocarbons, carbon monoxide, methane, sulfur
dioxide, and possibly other contaminants.

Industrial-plant manufacture or use of aldehydes will always
result in the release of some aldehydes to the environment. Although
the present industrial control methods appear to be well conceived and
efficient removal of aldehydes is theoretically possible, continued
measurement of this emission is advised. This applies not only to
plants preparing formaldehyde and acetaldehyde, the most important
commercial aldehydes, but especially to the manufacture of the highly
toxic aldehyde, acrolein.

Installation of urea-formaldehyde foams as insulation material has
often resulted in excessive formaldehyde emission. At least a
substantial portion of the emission can be attributed to poor
installation techniques or improper use of materials. It is
recommended that companies supplying the materials develop improved

14

reactants, training procedures, and installation procedures for local
contractors. Potential customers should also be made aware that
formaldehyde will be emitted for some period after installation, even
with the best combination of installation procedures and materials.
Such emission to the atmosphere and the aquatic environment is not
well characterized in most cases.

The aldehydes in the aquatic and terrestrial environments are
potential sources of human exposure. Thus, it is recommended that
pollution of the aquatic and terrestrial environments be studied to
determine the hazardous concentrations of aldehydes to which humans
and other organisms are likely to be exposed.

QUANTITATIVE ANALYSIS OF ALDEHYDES IN THE ENVIRONMENT

The ultimate value of any research related to the environmental
effects of the aldehydes depends on the reliability, reproducibility,
and accuracy of the analytical data that demonstrate the nature and
amount of the aldehydes. Although many analytical procedures have
been used in previous aldehyde studies, there are substantial problems
associated with most of those in use today.

No technique common to the analysis of all aldehydes can yet be
recommended. A series of more limited techniques that are widely
used, generally for an individual aldehyde like formaldehyde, are
discussed in Chapter 6. Very few of these are without fault in one or
more respects: calibration, sampling procedure, or method of
analysis. These limitations prevent their recommendation. Many of
the techniques have common procedures, and hence common faults.
Improved procedures for calibration, sampling, and analysis that are
now recognized must be coupled to produce a series of refined,
although still limited, techniques that can be recommended as standard
measurement procedures and thus be applied immediately. However,
emphasis should be on developing new techniques to secure the greatest
benefit in the shortest time.

Wet-chemical spectrophotometric methods of analysis are the most
practical and best-established methods for determining aldehydes, and
their continued use is recommended for the immediate future, with some
stipulations. First, there must be recognition that the information
provided by these methods is limited; they generally measure either an
individual aldehyde or the aldehydes as a class without
discrimination. The accurate assessment of specific aldehydes as
environmental pollutants may require the application of several
methods. Second, recommendation of these methods of analysis should
not impede investigations of promising alternatives. Possible
improvements such as increased sensitivity, decreased analysis time,
or the simultaneous quantitative determination of several
aldehydes should be actively sought. With these two stipulations, we
recommend the seemingly optimal wet-chemical spectrophotometric
methods for aldehydes, of which the most widely used for the
determination of formaldehyde are based on chromotropic acid and
pararosaniline reagents. However, there are serious problems with

15

methods that use chromotropic acid: determination of optimal analysis
conditions, interfering substances, and lower sensitivity relative to
alternative reagents. The pararosaniline method appears to be a
suitable replacement for the chromotropic acid method. Its
sensitivity is high, and interferences are minimal. Extensive testinc
should be continued, to confirm its use as a standard method for the
analysis of formaldehyde in air. For the near future, the
acetylacetone method shows the greatest promise, by virtue of its
greater sensitivity, and should be evaluated for use in the analysis
of air.

In view of the limitations of information obtained by measuring
the total aldehyde content of mixtures that may have various ratios o
aldehydes with substantially different toxicity, it is recommended
that the methods of analysis for "total" aldehyde not be used in
future studies involving atmospheric aldehydes.

Techniques for the quantitative analysis of a large number of
specific aldehydes in the environment are highly desirable for
maximizing information. Such techniques probably will rely on
gas-phase or liquid-phase chroma tography for separation. Because sue!
techniques also rely on derivatization of the aldehydes, one possible
approach would involve the use of passive monitors containing a
derivatizing trapping agent in conjunction with a chromatographic
separation method and analysis.

Techniques that can provide real-time measurements at field
sampling sites are extremely desirable. It may be possible to develo
continuous monitors that use established wet-chemical spectrophoto-
metric methods of analysis; this would require little chemical
research, but considerable engineering development. A number of
alternative direct spectroscopic measurement techniques have been use'
in laboratory and atmospheric studies, but it is difficult to
recommend these for a large number of sites without promise of future
reduced cost and increased portability. However, it should be
recognized that such direct techniques can provide analytical
information based on characteristic spectral line structure and
position; this allows an excellent check on possible unforeseen
interferences that may be present in the less direct aqueous-phase
spectrophotometric methods.

There are two methods of analysis to be considered for measuring
the highly toxic and environmentally important aldehyde, acrolein.
The method using 4-hexylresorcinol is well established, and its
continued use is recommended. Field mishaps may be minimized and
sample stability improved by collection in a bisulfite solution. A
second fluorimetric method using m-aminophenol shows promise and coul
offer substantially improved sensitivity. Further tests of this
second system are recommended.

To assess the health impact of aldehydes as environmental
pollutants, it is desirable to expedite measurements so that a maxima
number of samples may be analyzed. With this in mind, we note that
passive monitors offer a great potential for expediting large-scale
sampling. Therefore, it is recommended that research be directed
toward perfecting a passive-monitor trapping agent consistent with on

16

r more of the methods of analysis currently available. The
ollection of aldehydes on solid sorbents and later removal with an
ppropriate solvent represents one avenue of research. If they are
onsistent with available methods of analysis, passive monitors could
e deployed with minimal delay.

There is no wet-chemical spectrophotometric method of analysis now
vailable for the specific determination of acetaldehyde . Because the
oxicity of acetaldenyde is low, relative to that of other aldehydes,
his analysis may seem unnecessary and unimportant. However,
icetaldehyde is a major source of peroxyacetyl nitrate in the urban
nvironment, so it is very important to develop methods that allow the
lonitoring of this major precursor of a highly toxic compound. It is
'vident that the development of techniques for the quantitative
inalysis of all the individual aldehydes present will permit the
leasurement of acetaldehyde.

HEALTH EFFECTS OF FORMALDEHYDE

There is an urgent need for research to resolve several important
questions related to the health effects of formaldehyde. The most
loteworthy needs that the Committee has identified are outlined here.

It is not known what fractions of persons with asthma, atopic
subjects, nonatopic persons, and patients with chronic obstructive
Lung disease constitute susceptible populations. Quantitative
information on the proportion of the general population that is
susceptible to the effects of formaldehyde and on the extent of the
variability in response among this population may be obtained with
appropriate epidemiologic techniques. A practical means for
identifying susceptible subjects in the population is needed. Whether
children, infants, pregnant women, older persons, and persons with
specific medical conditions (e.g., heart disease) are also susceptible
to the effects of formaldehyde also needs to be explored.

Controlled studies of the range of irritation responses to
formaldehyde at concentrations below 1 ppm are few. Both
epidemiologic studies and human inhalation experiments are necessary
to assess the risk more precisely. These studies should include
several formaldehyde concentrations below 1 ppm.

More objective means for determining human eye, nose, and throat
irritation responses are needed. The reported studies have relied on
subjective complaints. Because small-airway involvement may be a
manifestation of lung involvement, future studies should incorporate
tests of small-airway function, as part of both epidemiologic and
chemical inhalation studies with humans.

In general, to identify specific health effects associated with
exposure, information is needed from extensive, long-term

17

epidemiologic studies that include persons from selected occupational
sites and residences (conventional homes and mobile homes) and that
involve cohorts (especially pregnant women, neonates, older children,
and the infirm) and proper controls. Investigations should explore
ways of identifying exposure with biologic tests (e.g., on urine or
blood) and comparing them with the concentrations of chemical
contaminants in air. Data on dose-response relationships are needed
for use in developing control strategies. In addition, there must be
careful documentation to show the relationship of human exposure to
complaints, particularly nonspecific symptoms (headaches, tiredness,
thirst, drowsiness, etc.).

Human epidemiologic investigations assessing the carcinogenic
potential of formaldehyde are lacking. Human studies should address
carefully the magnitude and duration of exposure, cigarette-smoking
habits, and the presence of other environmental contaminants, such as
bis (chloromethyl) ether , or confounding factors. Animal studies should
include a number of different species, including primates. The
importance of hyperplasia and metaplasia of nasal mucosa in humans and
animals requires clarification, including the natural history and
sequence of changes, dose-response relationships, the regression of
lesions after removal of formaldehyde exposure, and potential
screening tests of value (such as nasal swabs for cytologic
examination) .

Long-term effects of continuous low-dose exposure to formaldehyde
are not known; particularly needed is an assessment of the mutagenic,
embryotoxic, and teratogenic potential through human epidemiologic and
laboratory animal studies. The observation of the mutagenic potential
of formaldehyde in a wide variety of organisms points to the need for
new work to ascertain the mutagenic and carcinogenic potential of
formaldehyde in mammalian germinal or somatic cells. This information
is required to evaluate properly the hazard to persons exposed to
formaldehyde.

The mechanism of the airway response to formaldehyde is not
known. Controlled inhalation studies with histamine or methacholine
challenge tests are needed for assessing formaldehyde's effects on
airways. Tests can be performed before and after low-dose exposures.
In addition, investigations should be made to identify how
formaldehyde sensitizes the airways and to determine whether there is
an immunologic or nonimmunologic basis.

Epidemiologic studies of dermatitis due to formaldehyde are needed
in determining prevalence, clinical history, and other contributing
factors. Epidemiologic studies evaluating the risk and nature of skin
reactions should include formaldehyde patch tests. It is not known
whether airborne formaldehyde can cause allergic skin reactions.
Therefore, studies of this and other routes of exposure and of the
skin metabolism of formaldehyde are needed.

The effects of formaldehyde on nasal and lung defense mechanisms
have not been well studied. More investigations showing the
relationship of formaldehyde exposure and resulting effects on nasal
and bronchial ciliary motility, alveolar machrophage function, and
other defense processes are needed.

18

Limited information is available on the interactions of
formaldehyde with other air pollutants. These studies are best
performed as inhalation experiments, in which important variables can
be controlled better than in field studies. The persons studied
should include those believed to be susceptible to the effects of
formaldehyde.

HEALTH EFFECTS OF SOME OTHER ALDEHYDES

Some of the higher-molecular-weight aldehydes appear to have
effects that demand confirmation and quantitative evaluation to
provide the proper health-risk evaluation and development of control
strategies. Acetaldehyde was reported to be both embryotoxic and
teratogenic in a single study in mice. These effects were similar to
those of ethanol in humans. Because of the metabolic relationship
between ethanol and acetaldehyde, the effects on the embryo need to be
examined more extensively in other animal models. Acetaldehyde was
shown to have chromosome-breaking activity in mammalian cells; that
indicates that it may have mutagenic potential. Epidemiologic
evidence also indicates that alcoholics have a higher risk of cancer.
Again, the close metabolic relationship of acetaldehyde and ethanol
requires that the carcinogenic potential be assessed. None of the
existing studies provides sufficient information for an analysis of
risks to humans.

Acrolein is seemingly one of the most acutely toxic and highly
irritating of the aldehydes commonly encountered in the environment.
In a single study in rats, acrolein was not found to be embryotoxic.
However, the fetuses were not examined for malformations. Therefore,
no information on the teratogenic potential of acrolein is available,
and this should be studied further. Acrolein was not shown to be
carcinogenic in a study on hamsters; there was a minimal effect on the
carcinogenicity of benzo[a]pyrene. Both the cocarcinogenic effect and
the carcinogenic potential of acrolein need to be evaluated further in
other animal models, to determine whether the hamster is refractory in
acrolein exposure studies. The intense eye irritation that is induced
in humans by acrolein at very low concentrations should be
investigated to establish the mechanisms that cause the severity of
the reactions.

Investigations are also needed to characterize further the effects
of the common aldehydes (e.g., butyraldehyde and acrolein) on humans,
especially at concentrations present in the workplace, home, and
general environment. Studies are needed to assess the importance of
low-dose chronic exposures and interactions with other atmospheric
contaminants .

Further studies are required to establish the suggested role of
formaldehyde, acrolein, and possibly other aldehydes in eye irritation
associated with high concentrations of photochemical smog. Tests for
possible relations of eye irritation and formic acid, peroxyacetyl
nitrate, and other products derived from the aldehydes should be made.

19

Human exposure to atmospheric aldehydes may be repetitive , as in
occupational situations, or continuous, as in a residential
environment contaminated with aldehydes from cigarette smoke,
automobile exhaust, or out-gassing from aldehyde-containing consumer
products. Animal studies are needed to investigate the
pathophysiologic effects, immunologic aspects, and element's of
sensitivity associated with continuous chronic exposure to aldehydes,
for use in assessing the potential hazards and the results of
epidemiologic studies.

EFFECTS OF ALDEHYDES ON VEGETATION

Several overt and subtle effects of aldehyde phytotoxicity have
been reported in the very few studies of aldehydes that have been
conducted. To understand the phenomenon fully, systematic studies
like those conducted with the major air pollutants sulfur dioxide,
ozone, and hydrogen-fluoride are recommended. The more common
aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, and
acrolein should be used to screen economically important crops for
sensitivity. Plant factors such as genetic variability, age, and
nutrition and climatic and edaphic factors that influence plant growth
should be examined to determine whether they increase plant
susceptibility. Dose-response data should be obtained for the major
aldehydes singly and in combination with each other and with other
pollutants. In addition to visible injury (obvious symptoms),
biochemical and physiologic alterations in plants should be assessed.
The discovery of an aldehyde-sensitive "indicator" plant would prove
useful in detecting aldehyde pollution in the environment.

EFFECTS OF ALDEHYDES ON AQUATIC ORGANISMS

Available data on the toxicity of aldehydes to aquatic organisms
show that the acute toxicity of aldehydes can vary considerably. No
toxicity data are available on the majority of the aldehydes that have
been identified in aquatic systems. Although chronic effects are
unlikely because of the instability of aldehydes in water, it is
recommended that a program be developed and implemented to assess
systematically the probable hazard of the commonly encountered
aldehydes to aquatic life and to identify those which should be
controlled.

CHAPTER 4
COMMERCIAL PRODUCTION, PROPERTIES, AND USES OF THE ALDEHYDES

The aldehydes are a very important class of organic compounds;
they are characterized by the presence of the formyl functional group,

which we represent in this report as -CHO. The general structural
formula of the aldehydes can be written as

R-C-H

The first member of the aldehyde family is formaldehyde (HCHO) , in
which the R group is a hydrogen atom. For the higher aldehydes,
acetaldehyde (CH 3 CHO) , propionaldehyde (C 2 H 5 CHO) , and
n_-butyraldehyde (n-C 3 H 7 CHO) , the R groups are CH 3 , C 2 H 5 , and
n-C 3 H 7 , respectively. The physical properties of the aldehydes
that have some potential importance in the environment are summarized
in Table A-l of the Appendix. Table A-2 summarizes the uses of
selected aldehydes and presents the various synonyms for their names.

Formaldehyde is the most common and important aldehyde in the
environment, and the properties of its several common forms are
considered in some detail in the first section of this chapter. In
subsequent sections we consider the methods of aldehyde production and
the manufacture of aldehyde-containing consumer products.

PROPERTIES OF VARIOUS FORMS OF FORMALDEHYDE
MONOMERIC FORMALDEHYDE

Monomer ic formaldehyde is a colorless gas that condenses to form a
liquid of high vapor pressure that boils at -19C (760 Torr) ; it forms
a crystalline solid at -118C. It has a pungent odor that is highly
irritating to the exposed membranes of the eyes, nose, and upper

20

21

respiratory tract. In the pure dry, liquid form at low temperatures
(-80 to -117C) , it does not polymerize rapidly; its stability depends
on its purity, and it must be held at a low temperature to avoid
polymerization. It is not commercially available in this form, but
can be prepared for laboratory use by the original method of Spence
and Wild. 23

The molecule of gaseous formaldehyde in ambient air is designated
by the molecular formula HCHO or the structural formula,

H

> =
H

TRIOXANE

Trioxane is the cyclic trimer of formaldehyde (trioxymethylene) .
It has the molecular formula of 03^03, with three HCHO units
per molecule. Its structural formula is:

CH 2

CK M)

I I

CH 2 CH 2

In pure form, it is a colorless, crystalline solid that melts at
61-62C, and it boils at 115C. It has a chloroform-like odor, and it
is not irritating. It is combustible and burns readily when ignited
(flash point, 45C) . It is soluble in water, and saturated solutions
contain approximately 21 g/100 cc at 25C.

PARAFORMALDEHYDE

Paraformaldehyde is a colorless solid in a granular form with an
odor characteristic of monomer ic formaldehyde. It is prepared by
condensation of methylene glycol (HOCH 2 OH) , and its composition is
best expressed by the formula HO- (HCHO) Q -H. Commercial grades of
Paraformaldehyde usually specify not less than 95% formaldehyde by
weight, and they may contain up to 99%. Paraformaldehyde melts over a
wide temperature range (120-170C) , which depends on the degree of
polymerization. At room temperatures, it gradually vaporizes largely
as the monomer ic formaldehyde with some water formation, and the rate
is increased by heating. Thus, it is commonly used as a source of
formaldehyde for disinfecting large areas. It dissolves in hot water,
and a solution of approximately 28% can be obtained by agitating it
with water at 18C for 5 wk.

22

FORMALIN

Formalin is the principal form in which formaldehyde is marketed;
it is an aqueous solution that ranges in concentration from 37 to 50%
by weight. The National Formulary solution contains not less than 37%
formaldehyde with methanol (usually 6-15%, depending on the usage
requirements) to suppress polymerization. It is a clear solution with
the strong pungent odor of formaldehyde. Cloudiness is usually due to
polymers, which form at various rates that depend on methanol content
and storage temperature. The solution is slightly acid 0.005-0.01 M,
calculated as formic acid.

In aqueous solutions, the dominant form of the formaldehyde is
methylene glycol; in concentrated solution, it is one of many polymer
molecules, HO- (CH 2 0) n -H, polyoxymethylene glycol.

SOME CHEMICAL REACTIONS OF FORMALDEHYDE

Formaldehyde vapor is relatively stable with respect to thermal
decomposition; at temperatures above 400C, it decomposes to form
carbon monoxide, hydrogen, and methanol in the overall reactions,

2HCHO + CH 3 OH + CO (1)

and HCHO - CO + H 2 (2)

Reaction 1 is catalyzed on metal surfaces and must occur
heterogeneously. * l "* Reaction 2 may occur as written i.e., a
direct decomposition into two stable molecules or it may occur by a
free radical pathway initiated by a primary rupture of a
carbon-hydrogen bond: HCHO + H + HCO; H + HCHO H 2 + HCO; HCO
+ M t- H + CO + M.

The carbon-hydrogen bonds in the formaldehyde molecule are
relatively weak, and the rate constants for the hydrogen-atom
abstraction reactions by free radicals are large (see Chapter 5) . For
example, the HO-radical attack on formaldehyde, HO + HCHO + H 2 +
HCO, has a rate constant that is near the collision number and is
independent of the temperature.

Formaldehyde monomer vapors at pressures above about 0.5 Torr show
a tendency to polymerize at room temperature. 22 The equilibrium
vapor pressure of monomeric HCHO over polymeric HCHO is much higher at
high temperatures, and monomer pressures of several hundred Torr can
be maintained readily for several hours without substantial
polymerization if the containing vessel is heated to 100C or higher.

In the aqueous phase, formaldehyde is oxidized readily by even
mild oxidizing agents, such as Ag(NH3) 2 + , and this property has
been exploited in the development of several wet-chemical analytical
methods for formaldehyde.

23

OXIDATION AND REDUCTION REACTIONS

On oxidation under controlled conditions in the gaseous or
dissolved state, formaldehyde may be converted in part to formic acid,
or under more highly oxidative conditions to carbon monoxide (with
some carbon dioxide), and water. The photooxidation of formaldehyde
in the gas phase leads to carbon monoxide, hydrogen, hydrogen
peroxide, formic acid, and some other metas table products (see Chapter
5) . Per formic acid is produced under special conditions through the
oxidation of formaldehyde solutions at low temperatures.

REACTIONS OF FORMALDEHYDE WITH FORMALDEHYDE
Cannizzaro Reaction

This reaction involves the reduction of one formaldehyde molecule
with the oxidation of another. Although it is normally catalyzed by
alkalies, the reaction can occur when formaldehyde is heated with
acids at 40-60C: 2HCHO(aq) + H 2 * CH 3 OH + HCO 2 H. At 70C,
the reaction may proceed through an aldol condensation, wherein
carbohydrates are formed. Formaldehyde and other aldehydes that do
not possess alpha-hydrogen atoms do not undergo ordinary aldol
condensations, but can react almost quantitatively in alkaline
solution and liberate hydrogen:

HCHO(aq) + NaOH * HC0 2 Na + H 2
H 2 + HCHO(aq) + CH 3 OH

Tischenko Reaction

Polymers of formaldehyde when heated with either aluminum or
magnesium metal powder form methyl formate:

2 HCHO( polymer) * HC0 2 CH 3

Polymerization Reactions

The formation of resinous products on reaction with other
chemicals is one of the most useful characteristics of formaldehyde
and is the reason for its immense importance in the synthetic resin
industry. Under suitable conditions, the molecules of many compounds
are linked together by methylene groups when subjected to the action
of formaldehyde. Phenol- and urea-formaldehyde resins are
polymethylene compounds of this type.

Two distinct mechanisms are probably involved in resin-forming
reactions: the polycondensation of simple methyl derivatives and the
polymerization of doubled-bonded methylene compounds. Although in
some cases the mechanism is definitely one or the other of the two, it

24

is often not clear which is followed, and both may play a part in some
instances. Recent evidence indicates that the formation of
urea- formaldehyde resins, which used to be regarded as a simple
polycondensation of methylol ureas, may actually involve the primary
formation of a methylene urea that then polymerizes to give a cyclic
trimethylenetriamine whose methylol derivatives are finally
cross-linked by condensation.

Thermoplastic resins are the result of simple linear

condensations, whereas the production of thermosetting resins involves
the formation of methylene cross-linkage between linear chains. Both
types may be produced from the same raw materials by variations in the
relative amounts of formaldehyde used, the conditions of catalysts,
and the temperature. However, with compounds whose molecules present
only two reactive hydrogen atoms, only thermoplastic resins can be
obtained.

A diverse group of organic compounds including alcohols, amines,
amides, proteins, phenols, and hydrocarbons form resins with
formaldehyde.

INDUSTRIAL PRODUCTION AND USES OF THE ALDEHYDES

Aldehydes as a family are produced in the United States at a rate
of several billion pounds per year. 25 An even greater quantity is
produced in other parts of the world. The more important aldehydes
(on the basis of production rates) are made with feedstocks obtained
from petroleum or natural gas; hence, they are generally considered to
be petrochemicals.

Several aldehydes find large and generally major uses as
feedstocks for the production of other chemicals. Considerable
amounts of several aldehydes are used captively in a given
plant i.e., they are produced and used in the same plant. Large
quantities of aldehydes, however, are transported to other plants or
locations for use. The following factors are considered here with
respect to the most important aldehydes: industrial processes used
for production, annual rates of production, end uses, and properties.

FORMALDEHYDE
Production

Formaldehyde is the most important aldehyde in the United States
and in the remainder of the world, on the basis of rates of
production. 25 Most formaldehyde is stored and transported as
aqueous solutions containing 37-50% formaldehyde and 1-15% methanol.
In 1978, total production capacity in the United States was about 9 x
10 Ib of aqueous solution, or about 3.3 x 10 Ib on an anhydrous
basis. Actual production is estimated to be only 70% of capacity, or
approximately 6.3 x 10 9 Ib of formaldehyde solutions per year. It

25

is estimated that 65% of the formaldehyde produced is used in the same
plant in which it is produced.

Costs for transporting formaldehyde tend to be high, because water
and methanol also need to be transported. Hence, as a general rule,
formaldehyde solutions are transported only relatively short
distances, and little formaldehyde is exported or imported. Several
large formaldehyde plants are near lumber plants in the South and the
far West, inasmuch as the two largest uses for formaldehyde solutions
are in production of plywood and particleboard.

Methanol is the starting feedstock for commercial production of
formaldehyde. 5 7 10 15 21 27 For some 40 or 50 yr, methanol has
been produced almost exclusively by the reaction of carbon monoxide
and hydrogen under high pressure in the presence of catalysts. Both
carbon monoxide and hydrogen are generally obtained from natural gas
or petroleum fractions. Other materials that, at least in theory, can
be used are coal, shale oil, oil from tar sands, and cellulose. Coal
has already found limited use, and it will probably increase in the
future. For at least the next 10 or 15 yr, however, petroleum-based
hydrocarbons will probably remain the preferred feedstock for
production of methanol.

Methanol (wood alcohol) was produced in the early part of this
century primarily from wood. But this process cannot compete
economically with the process that uses petroleum-based feedstocks.
Another process that is no longer economically feasible is a process
in which propane and butane are partially oxidized to produce a wide
variety of oxygenated products, including methanol, formaldehyde, and
acetaldehyde. 2

In the United States, 16 companies produce formaldehyde;
capacities of formaldehyde plants vary widely from about 14 to 600 x
10" lb/yr. 15 Three companies (Celanese, Borden, and Du pont) have
over 50% of our national capacity. Two quite different processes are
used. 5 7 10 19 20 In one, a mixture of methanol and oxygen is
passed over a silver catalyst. The main reaction is the
dehydrogenation of methanol:

Ag

Part of the hydrogen is oxidized with oxygen to produce water vapor.

In the other process, a mixture of methanol and air is passed over
a catalyst consisting of molybdenum and iron oxides. The main
reaction is this oxidative dehydrogenation of methanol:

Mo,Fe
CH 3 OH + 2 OXlde ^ HCHO + H 2

Relative advantages of the two processes have been discussed in
considerable detail by Diem, 7 Sleeman, 21 and Chauvel et al. 5
The capital costs of the silver-catalyst process are higher, but its
operating costs are lower. The ratio of formaldehyde to methanol in

26

the product solution is normally higher in the oxide-catalyst process;
this product is preferred for some end uses. 5

Uses

Major uses for formaldehyde have been reported elsewhere. 9 2 *
About 50% of the formaldehyde produced is consumed in the production
of urea-formaldehyde and phenol-formaldehyde resins. These resins are
used in the production of plywood, particleboard, foam insulation, and
a wide variety of molded or extruded plastic items. Another 20-25% is
used in the production of other resins or high polymers, including
polyacetals, melamine resins, and alkyd resins. Hence, 70-75% of the
formaldehyde is used in the production of high-polymeric resins or
plastics. Formaldehyde is also used to produce
hexamethylenetetramine, pyridine, trioxane, paraformaldehyde,
chelating agents, and nitroparaffin derivatives. Formaldehyde
solutions (often referred to as formalin) are used as disinfectants,
embalming fluids, and textile-treatment agents and in leather and dye
manufacture.

ACETALDEHYDE (CH-jCHO)

Production

In 1978, production capacity for acetaldehyde in the United States
totaled about 1.7 x IQr Ib, but actual production was approximately
1.0 x 10 9 Ib. 17 2 " Acetaldehyde is generally stored and
transported as a liquid. Because it has a normal boiling point of
20.8C, storage vessels must be capable of withstanding high pressures,

About 80% of the world's aldehyde is produced by controlled
oxidation of ethylene with an aqueous solution of palladium and cupric
chlorides as catalysts. x The overall desired reaction is as follows:

C 2 H 4 + 0.502 + CH 3 CHO

This acetaldehyde process was first commercialized in about
1960; 12 two versions are now used industrially. A two-stage version
was developed by Wacker Chemie, but Farbwerke Hoechst has developed a
one-step version. These two versions are often referred to as the
Wacker process and the Wacker-Hoechst processes, respectively. 11 In
both, more than 93% of the ethylene feedstock is converted to and
recovered as acetaldehyde. Carbon dioxide, water vapor, and
chlorinated hydrocarbons are byproducts.

In the one-step process, oxygen is used as the oxidant. It is
mixed with ethylene, and the mixture is bubbled upward through the
catalytic solution. About 25% of the ethylene reacts per pass over
the catalyst, and most of the unreacted ethylene is recovered and
recycled to the reactor .

27

In the two-step process, ethylene is bubbled upward through the
catalytic solution. The following reactions are the predominant ones
in the first step of the process:

C 2 H 4 + PdCl 2 + H 2 * CH 3 CHO + Pd + 2HC1
and Pd + 2CuCl 2 PdCl 2 + 2CuCl

In the second step, the catalyst solution is regenerated with air in a
separate reactor, as follows:

2CuCl + 2HC1 + 0.50 2 * 2CuCl 2 + H 2

Almost all the ethylene reacts in a single pass through the reactor in
the two-step version; hence, recovery and recycling of ethylene are
not critical as a rule.

In both versions of the process, acetaldehyde is separated from
the exit gas stream from the reactor by water absorption, and an
aqueous solution of acetaldehyde is produced. Unreacted ethylene, if
any, is recycled to the reactor. There is always a need for a vent
stream, to remove chlorinated byproducts. This vent stream contains
some ethylene and low amounts of acetaldehyde; the exact
concentrations of these materials in the vent stream apparently have
never been reported for any specific industrial plant. If necessary,
however, an absorber could be designed and operated to remove
essentially all acetaldehyde from the vent stream. To prevent most of
the combustible hydrocarbons, including acetaldehyde, from escaping to
the surroundings, it is generally more economical to send the vent
stream to a flare or to the furnace. In the one-step process, the
vent stream has a substantial fuel value.

Before development of the Wacker technology, the following two
processes were of major importance:

Hydration of acetylene. This process was commercialized in
Germany during World War I. Several modifications have been reported,
but the process has not been competitive with the Wacker-Hoechst
process, because of the relatively high price of acetylene, compared
with ethylene.

Dehydrogenation of ethanol. In many respects, this process
is similar to the one for production of formaldehyde from methanol.
To make its use feasible in the future, the required ethanol reactant
must be available at a much lower cost than ethylene.

Although these two process are still used to a limited extent, it
is unlikely that they will be used in any new plants in the near
future.

In transporting or storing acetaldehyde, extensive precautions
must be taken to prevent leaks and ensure safe conditions, because
this aldehyde boils at room temperature. When mixed with air, it is
highly flammable and reacts to form acetic acid, highly explosive
peroxides, and other products. It is transported in drums or
insulated trucks or tank cars. Specific information was not found on
acetaldehyde concentrations in the atmosphere in or near acetaldehyde
plants.

28

Uses

About 60% of the acetaldehyde produced is used as feedstock for
the production of acetic acid and acetic anhydride. The remaining 40%
is used in the production of pentaerythritol, peracetic acid,
pyridine, crotonaldehyde, 1,3-butylene glycol, and various other
chemicals. Hester and Himmler 12 reviewed the numerous chemicals
manufactured in 1958 from acetaldehyde.

ACROLEIN (CH 2 =CHCHO)

Production

Acrolein is produced in the United States by Shell Chemical Co.
and Union Carbide Corp.; the annual production in 1978 was estimated
at about 45 x 10 6 Ib. 25

Acrolein has been produced by several processes in the past,
including condensation of formaldehyde with acetaldehyde and the
pyrolysis of diallyl ether. 26 The method currently used is the
catalytic oxidation of propylene; a mixture of propylene, air, and
steam in a mole ratio of approximately 1:10:2 is passed over a
catalyst of mixed metal oxides. Acrolein yields, on the basis of
inlet propylene feed, are about 70%, but substantial amounts of
acetaldehyde and acrylic acid are also produced. A water absorption
unit and distillation are used for recovery and separation of
acrolein, acetaldehyde, and acrylic acid.

Acrolein is a colorless liquid; it is highly volatile and highly
reactive. Because it is highly irritating, absorbers are used to
minimize acrolein losses to the atmosphere. In addition, gaseous
emission streams are generally sent to either a flare or a furnace, to
destroy acrolein in any gas stream by combustion before it is
exhausted to the atmosphere. Careful design and close attention to
operating and maintenance procedures are necessary to minimize
acrolein losses or leaks at pumps, valves, and storage vessels.
Undesired reactions of acrolein, such as polymerization, are minimized
by adding inhibitors and stabilizers to the liquid acrolein.

Uses

Approximately half the acrolein produced is used as a feedstock
for production of glycerine, 26 and about 25% to produce the amino
acid methionine, an essential protein added to various foods. The
remaining 25% of acrolein is used in the production of many chemicals ,
including glutaraldehyde, 1,2,6-hexanetriol, quinoline, penta-
erythritol, cycloaliphatic epoxy resins, oil-well derivatives, and
water-treatment chemicals.

29

HIGHER ALIPHATIC ALDEHYDES
Production

The Oxo process is the application of a chemical reaction called
oxonation, or more properly hydroformylation, for production of
03-0^5 aliphatic aldehydes. 13 Carbon monoxide and hydrogen are
caused to react with the double bond of an olefin to produce an
aldehyde with at least one more carbon atom than the olefin. In the
case of ethylene, the overall reaction for production of
propionaldehyde is as follows :

CH 2 =CH 2 + CO + H 2 - CH 3 CH 2 CHO

In the case of proplyene, both n-butyr aldehyde and isobutyraldehyde
are produced.

In the past, cobalt carbonyls were used almost exclusively as
catalysts for the Oxo process, and relatively high pressures, often
200-400 atm, were required. 13 In the last few years, various
catalysts have been proposed that offer a variety of advantages,
including higher yields, improved product compositions, and lower
operating pressures. Rhodium catalysts, for example, are now widely
used in Oxo processes of at least several olefins. 16

A portion of the aldehyde formed is hydrogenated to produce
alcohols. For example, some propionaldehyde is hydrogenated to
1-propanol, some iv-butyraldehyde to 1-butanol, and some
isobutyraldehyde to 2-butanol.

Propionaldehyde is produced by two American manufacturers, Eastman
Kodak Co. and Union Carbide Corp. Production in 1978 was estimated at
over 190 x 10 6 lb. 25 About 750 x 10 6 Ib of butyraldehydes were
produced in 1976. Major American' producers of butyraldehyde are
Badische, Celanese Corp., Eastman Kodak Co., and Union Carbide Corp.

The Oxo process is used for the manufacture of several aldehydes
that are consumed in the production of plasticizers. In such cases,
the aldehydes are hydrogenated to produce alcohols; the alcohols then
react with acids to produce the esters that serve as plasticizers.

Uses

Propionaldehyde is used primarily as a chemical intermediate; the
percentages consumed in this country for different purposes are
approximately as follows: 1-propanol, 40%; propionic acid, 37%; and
trimethylolethane, 23%. Butyraldehydes are used as chemical
intermediates in the production of 1-butanol, 2-butanol,
2-ethyl-l-hexanol , and a wide variety of specialty chemicals. Over
1 x 10 9 lb of plasticizers are used each year in the preparation of
poly (vinyl chloride) plastics; C4~Ci2 aldehydes are used for this
purpose. Several of the higher aliphatic aldehydes,

30

particularly C^~ C 16 aldehydes, are used in the production of
detergents.

BENZALDEHYDE (C 6 H 5 CHO)

Benzaldehyde is a colorless or yellowish, highly refractive oil
with an odor resembling that of oil of bitter almonds; it is the
simplest aromatic aldehyde. 6 Total world production is probably
less than 10 x 10 6 Ib/yr .

Toluene is the feedstock used for production of benzaldehyde. At
least three processes have been used industrially: 6

Toluene is chlorinated to produce benzal chloride (or
a, ordichlorotoluene) , which is then hydrolyzed to produce

benzaldehyde.

Liquid toluene is oxidized in the presence of a catalyst,

such as manganese dioxide.

Toluene vapors are oxidized on a catalyst, such as vanadium
pentoxide.

Major U.S. producers of benzaldehyde are Benzol Products Co.,
Heyden, Newport Chemical Corp., and Tennessee Product and Chemical
Corp.

Uses

Benzaldehyde has important uses in dyes, Pharmaceuticals,
perfumes, and flavoring agents.

FURFURAL

EC' ^C-CHO

II II
HC CH

Production

Furfural (2-furaldehyde, furfuraldehyde, furfurol, or furol) , a
colorless liquid aldehyde is produced from a variety of agricultural
byproducts, including corncobs, oat hulls, rice hulls, bagasse,
cottonseed hulls, and paper-mill wastes. 8 It is soluble in most
organic solvents, but only slightly soluble in water. Furfural is
essentially a substituted furan; the aldehyde group is attached to the
five-member heterocyclic ring that contains one oxygen atom and two
carbon-carbon double bonds.

The raw materials used for furfural production are typically
brought together in dilute sulfuric acid, and the mixture is heated

31

pressure. On completion of the reaction the pressure is

-ed, causing the furfural to vaporize, with considerable water.

ude furfural is then purified primarily by distillation.

irfural is used in the manufacture of furan and several
lydrofuran compounds. It is used extensively as a selective
it in the production of lubricating oils, gas oils, diesel fuels,
jgetable oils. It also finds uses in the production of modified
L-formaldehyde resins and in the extractive distillation of
.ene.

MANUFACTURE OF ALDEHYDE-CONTAINING CONSUMER PRODUCTS
FORMALDEHYDE RESINS

Dme urea-formaldehyde resins emit formaldehyde over extended

3s. A brief discussion of the manufacturing (or polymerization)

ique used to produce these resins will help to explain the

ion problem and will suggest ways to eliminate or at least

ize it. The resins are prepared by causing urea to react with

Idehyde. 3 Each of the four hydrogen atoms in a urea molecule

tentially reactive. If urea and formaldehyde reacted on an

ly equimolar basis, the following reactions indicate the

tion of a typical so-called thermoplastic resin (or high polymer)

H-N-H H-N-CH 2 OH

C = +HCHO -- C =
I I

H-N-H H-N-H

urea

'he intermediate product formed is basically a monomer, and it
lerizes as follows to produce a thermoplastic resin and water:

H-N-CH 2 OH H-N-CH 2 -N-CH 2 OH

I I I

C = *- C = O C = O + H 2

H-N-H H-N-H H-N-H

32
Eventually:

r~ -~

H-N-CH 2 OH H N-CH 2 OH

n C = *- C = + (n-l)H 2

H-N-H H-i-H

Some additional formaldehyde is, however, needed to react with at
least a few of the unreacted -NH 2 groups and to provide chemical
cross-links between polymer chains. When such cross-links occur, the
desired thermosetting polymers or resins are produced. The amount of
formaldehyde added to the reaction mixture is critical, for the
following reasons:

An excess of formaldehyde results in faster polymerization or
cross-linking, which tends to lower manufacturing costs.

Sufficient formaldehyde is needed to provide adequate
cross-linking and to cause satisfactory properties in the final
product.

An excess of formaldehyde results in unreacted formaldehyde
in the final consumer product, which slowly diffuses from the product
and, especially in indoor applications, may result in increased
formaldehyde concentrations.

In addition to unreacted formaldehyde in urea-formaldehyde resins,
some formaldehyde may be formed by hydrolysis involving these resins.
These hydrolysis reactions are essentially the reverse of the
reactions shown above. When the resins are exposed to water or to a
humid atmosphere, some moisture is adsorbed; this results in the slow
formation and release of formaldehyde. Factors that affect the
release of formaldehyde from UF resins are discussed in greater detail
by Meyer . l 8

Urea-formaldehyde resins are a large and relatively old family of
high polymers that have been used in the production of numerous molded
plastic items. With respect to the release of formaldehyde to the
air, definite problems have occurred in the following applications:

Foams used in walls or attics of homes or other buildings for
insulation.

Particleboard.

Indoor plywood.

Paper products and some textiles.

In plywood and particleboard, the role of the resin is to act as
an adhesive to bind the thin sheets of wood and wood particles
together .

33

OTHER CONSUMER PRODUCTS

Several other high polymers that are prepared with formaldehyde
probably contain unreacted formaldehyde that may eventually be
emitted, phenol-formaldehyde (or phenolic) resins are prepared by
causing phenol and formaldehyde to react. Melamine resins are
reaction products of melamine and formaldehyde. The amount of
unreacted formaldehyde in the resin is obviously important. Phenolic
and melamine resins can be used as adhesives in the production of
plywood and particleboard . Phenolic resins are used because of their
desirable physical and chemical properties: they are quite resistant
to hydrolysis; they are relatively inexpensive , compared with
alternative resins (but somewhat more costly than urea-formaldehyde
resins) ; and there are often some problems with appearance. Although
plywood produced with phenolic resins is often dark or somewhat
stained, it is usually covered or coated in some way. Loss of
formaldehyde in such plywood, it it does actually occur, would be less
critical, because of outdoor application. There is little likelihood
that aldehyde would ever build up to high concentrations in the
ambient air.

Both phenolic and melamine resins are used in large quantities to
fabricate numerous molded or extruded plastic products. Because
fabrication is at high pressure, the final plastic product has
essentially no porosity. Hence, in these products, diffusion of
unreacted formaldehyde to the surface is extremely slow. There is no
evidence that formaldehyde emission is a problem with phenolic or
melamine plastic products.

Polyacetal resins are formed by polymerization of formaldehyde or
trioxane. Ethylene oxide is sometimes used as a comonomer , and the
polyacetal resin is a copolymer . At or near ambient conditions,
polyacetals are highly stable. Polyacetals that are homopolymers of
formaldehyde are thermally unstable at high temperatures, such as
might be experienced during a fire. In such cases, they decompose
quite rapidly and release formaldehyde.

REFERENCES

Aguilo, A., and J. D. Penrod. Acetaldehyde, pp. 115-162. In J.
J. McKetta, Ed. Encyclopedia of Chemical Processing and Design.
Vol. 1. New York: Marcel Dekker, Inc., 1976.
Albright, L. F. Commercial vapor phase processes for partial
oxidation of light paraffins. Chem. Eng. 74:165, 14 August 1967.
Billmeyer, F. W. Textbook of Polymer Science, pp. 468-475. 2nd
ed. New York: Wiley-Interscience Publishers, 1971.
Calvert, J. G., and E. W. R. Steacie. Vapor phase photolysis of
formaldehyde at wavelength 3130 A. J. Chem. Phys. 19:176-182, 1951,
Chauvel, A. R. , p. R. Courty, R. Maux, and C. Petitpas. Select
best formaldehyde catalyst. Hydrocarbon Processing 52 (9) :179-184,
1973.

34

6. Darshau, P., and A. P. Kudchadker. Benzaldehyde, pp. 171-182. In
J. J. McKetta, Ed. Encyclopedia of Chemical Processing and
Design. Vol. 4. New York: Marcel Dekker, Inc., 1977.

7. Diem, H. Formaldehyde routes bring cost, production benefits.
Chem. Eng. 85:83-85, 27 February 1978.

8. Dunlop, A. P. Furfural and other furan compounds, pp. 237-251.
In A. Standen, Ed. Kirk-Othmer Encyclopedia of Chemical
Technology. 2nd ed. Vol. 10. New York: Wiley-Interscience
Publishers, 1966.

9. Foster D. Snell Division. Preliminary Study of the Costs of
Increased Regulation of Formaldehyde Exposure in the U.S.
Workplace. Prepared for Formaldehyde Task Force, Synthetic
Organic Chemical Manufacturers Association. Florham Park, N.J.:
Booz, Allen and Hamilton, Inc., Foster D. Snell Division, 1979.
372 pp.

10. Gerloff, U. Compare BASF formaldehyde process. Hydrocarbon Proc.
Petrol. Refin. 46 (6) :169-172, 1967.

11. Guccione, E. Acetaldehyde via ethylene oxidation gets tryout in
single-stage design. Chem. Eng. 70:150-152, 9 December 1963.

12. Hester, A. S., and K. Himmler. Chemicals from acetaldehyde. Ind.
Eng. Chem. 51:1424-1430, 1959.

13. Kyle, H. E. Oxo process, pp. 373-390. In Standen, Ed. Kirk-Othmer
Encyclopedia of Chemical Technology. 2nd ed. Vol 14. New York:
Wiley-Interscience Publishers, 1967.

14. Longfield, J. E., and W. D. Walters. The radical-sensitized
decomposition of formaldehyde. J. Am. Chem. Soc. 77:6098-6103,
1955.

15. Lovell, R. J. Emissions Control Options for the Synthetic Organic
Chemicals Manufacturing Industry. Formaldehyde Product Report.
Knoxville Tennessee: Hydroscience, Inc., for U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards,
1979. [150] pp.

16. Low-pressure Oxo process yields a better product mix. Chem. Eng.
84:110-115, 5 December 1977.

17. Ma, J. J. L. Acetaldehyde. Process Economics Program Interim
Report No. 24A2. Menlo Park, California: Stanford Research
Institute, December 1976. [114] pp.

18. Meyer, B. Urea-Formaldehyde Resins. Reading, Mass.:
Addison-Wesley Publishing Company, Inc., 1979. 423 pp.

19. Sheldrick, J. E., and T. R. Steadman. Product/Industry Profile
and Related Analysis on Formaldehyde and Formaldehyde-Containing
Consumer Products. Part II. Products/Industry Profile on
Urea-Formaldehyde. Columbus, Ohio: Battelle Columbus Division,
for U.S. Consumer Product Safety Commission, 1979. [24] pp.

20. Sheldrick, J. E., and T. R. Steadman. Product/Industry Profile
and Related Analysis on Formaldehyde and Formaldehyde-Containing
Consumer Products. Part III. Consumer Products Containing
Formaldehyde. Columbus, Ohio: Battelle Columbus Division, for
U.S. Consumer Product Safety Commission, 1979. [39] pp.

21. Sleeman, D. G. Silver-catalyst process obtains high-strength
formaldehyde solutions. Chem. Eng. 75:42-44, 1 January 1968.

35

22. Spence, R. The polymerisation of gaseous formaldehyde. J. Chem.
Soc. 1933:1193-1197, 1933.

23. Spence, R. , and W. Wild. The preparation of liquid monomeric
formaldehyde. J. Chem. Soc. 1935:338-340, 1935.

24. Stanford Research Institute. Formaldehyde. In Chemical Economics
Handbook. Menlo Park, Cal.: Stanford Research Institute, 1979.

25. Suta, B. E. Production and Use of 13 Aldehyde Compounds. Menlo
Park, Cal.: SRI International, for U.S. Environmental Protection
Agency, Office of Research and Development, 1979. [32] pp.

26. Weigert, W. M. , and H. Haschke. Acrolein and derivatives, pp.
382-401. In J. J. McKetta and W. A. Cunningham, Eds.
Encyclopedia of Chemical Processing and Design. Vol. 1. New
York: Marcel Dekker, Inc., 1976.

27. Weimann, M. More-methanol formaldehyde route boasts many
benefits. Chem. Eng. 77:102-104, 9 March 1970.

CHAPTER 5

ALDEHYDE CONCENTRATIONS, EMISSION, AND ENVIRONMENTAL GENERATION
AND TRANSFORMATION REACTIONS

The aldehydes are introduced into the environment through a
variety of different pathways, which are considered in this chapter.
They are injected directly into the atmosphere with exhaust gases from
mobile sources and other equipment in which the incomplete combustion
of hydrocarbon fuels occurs. They arise from various industrial and
manufacturing operations and power generating plants that burn fossil
fuels, from uncontrolled forest fires and the open burning of wastes,
and from vegetation. Aldehydes are also generated in the atmosphere
through the interaction of various reactive species (ozone, hydroxyl
radicals, etc.) with hydrocarbons and some of their oxidation
products. In recent years, it has been recognized that formaldehyde
vapors may be released indoors, as well as outside, from various
domestic activities and, more importantly, from particleboard and
other building and insulation materials, chemically treated cloth, and
other products that are formulated with formaldehyde-containing
polymers. In fact, indoor concentrations of the aldehydes generally
exceed those found in the outside air today.

The buildup of aldehydes in the atmosphere as the result of their
direct release and their atmospheric generation is counterbalanced by
many aldehyde removal paths. The aldehydes absorb the ultraviolet
component of sunlight and undergo photodecomposition. They also react
rapidly with the ubiquitous, highly reactive, transient hydroxyl (HO)
free radical present in sunlight-irradiated atmospheres. Because of
the high water solubility of formaldehyde and the other
low-molecular-weight aldehydes, one expects the transfer of aldehydes
into rainwater, the oceans, and other surface waters.

The rates of generation of ozone and the peroxyacylnitrates in the
polluted atmosphere are strongly influenced by aldehyde
photodecomposition and other reactions.

The combined effects of aldehyde injection, generation, and
removal lead to a highly variable ambient concentration of the
aldehydes. Their concentration can become high (about 0.05 ppm) in
areas of high human activity and poor atmospheric ventilation. They
are also present in the natural atmosphere, and concentrations of
0.002-0.006 ppm are commonly monitored in remote regions.
Concentrations many times higher have been reported in some
nonoccupational indoor environments. This chapter considers the

36

37

aldehyde concentrations observed and then f in more detail, the many
processes that control these concentrations. Throughout this
document, the concentrations of gaseous aldehydes are usually given in
parts per million (ppm) or micrograms per cubic meter (yg/m 3 ) .
"Parts per million" as used here refers to molecules of the species in
question per million molecules of air at 25C and 1 atm; for these
conditions, concentrations expressed in the two units may be
interconverted according to the following relations:

concentration in yg/m 3 = (concentration in ppm) (40.87) (M) , and
concentration in ppm = (concentration in yg/m 3 ) (0.02447)/ (M) ,
where M is the molecular weight of the specific aldehyde, e.g., 30.03
for formaldehyde and 44.05 for acetaldehyde . "Parts per hundred
million" (pphm) , "parts per billion" (ppb) , and "parts per trillion"
(ppt) , which are used occasionally, refer to molecules of the species
in question per hundred million, billion, and trillion molecules of
air (at 25C and 1 atm), respectively.

ENVIRONMENTAL CONCENTRATIONS OF THE ALDEHYDES
THE CLEAN ATMOSPHERE

The formation of formaldehyde and the other aldehydes in the
natural unpolluted atmosphere is both anticipated in theory and
observed experimentally. Reported ranges of concentration of total
aldehydes in ambient clean air are as follows: Antarctica (1968) ,
<30. 0005-0. 01 ppm; rural Illinois and Missouri (1973), 0.001-0.002
ppm; Panama (1966), <0. 0002-0. 0027 ppm; and Amazon basin (1970),
0.001-0.006 ppm 25 (Breeding et^ al^ , 2 5 in reporting concentrations
in the central United States, cited references to other measurements
of formaldehyde in clean air) . Spectroscopic measurements
(high-resolution infrared absorption) have been used to identify
formaldehyde in the atmospheric column over Reims, France. 15 From
an analysis of the absorption line shapes at 2806.858 and 2869.871
cm"-'- and reference to theoretical formaldehyde concentration-
altitude profiles, Barbe et al. derived the approximate formaldehyde
concentration-altitude profile shown in Figure 5-1 (dashed line). 15
The formaldehyde concentration decreased from about 10 10
molecules/cc (about 0.0004 ppm) at ground level to about 10'
molecules/cc (about 0.00002 ppm) at 26 km. These measurements are in
reasonable accord with the theoretical estimates of Levy, 113 which
are shown in Figure 5-1 as the solid curve.

URBAN ATMOSPHERES

Aldehydes are among the most abundant of the carbon-containing
pollutant molecules in most urban atmospheres; only the hydrocarbons,
carbon monoxide, and carbon dioxide are at higher concentrations.
Shown in Figures 5-2, 5-3, and 5-4 are the aldehyde concentrations
observed in the areas of Los Angeles, California, in 1968, 15G

38

30

r

20-

10-

10 6

1 i i \n

10 7 10 8 lfl9 ifllO
CCH 2 0], MOLEC/CC

39

018

HI

1 1 1 1 >

0018

Q 16 -

^\ HUNTlNGTON

- 0016

^

.,"^ \ PARK

I 014 -

- 0014

LU

Q 012 -
< 010 -

/ ,^\

: /A-N\

-0012 E
-0010 ^

y 0.08-

J / S * v

-0008

1-

^ / / *

< 006 -

I ,

/ /**" ALIPHATIC

- OOOfi P

a. 0.04 -

-*' f ALDEHYDES

- 0004 DC

rf _ 002 s

1 ' --FORMALDEHYDE

- 0002 Z

*" E

LU

Q a n

z ^
^ c/i" 14

. EL MONTE

A

Z
-0014 O

QO 012

f \

O
-0012 z

16 010

-0010 UJ

Sf 008

- s'*** ^. 1/7" ~

- 0008 O
DC

<g 006

"4v

- 0006 O

|0 004

_ ^^*'

- 0004

DCZ

^^^^T m m^ ^

OO 002

_ ^*

- 0002

U.O

o

1 1 1 1 1

> 12

6

LOCAL TIME

FIGURE 5-2 Hourly aldehyde concentrations at Huntington Park and El Mon
Calif., October 22 1968. Reprinted with permission from Scott Research
Laboratories, Inc.

40

60-

o

I

CJ

I

I
o
o
o

40 -

HCHO

20 -

1000

1400 1600

TIME (hours)

1800

2000

FIGURE 5-3 Concentrations of formaldehyde and formic acid measured
in Riverside, Calif., at various times on October 14, 1977. Reprinted
with permission from Tuazon ^t aJL.

41

12

a 10-

Z ^
O

WORKDAY

QC

h-

Y\

ONCEN

\^K I
e -\^l

O

S-o^H

UJ

Q

^3

I

4-

UJ

Q

5

DC

2-

2

SUNDAY

]
12

16

I
20

24

HOUR OF DAY

FIGURE 5-4 Diurnal variation of formaldehyde concentrations measured
at Newark, N.J. , for different days of the week; averaged from data
taken from June 1 to August 31 for 19^, 1973, and 1974. Reprinted
with permission from Cleveland e_t al.

42

Riverside, California, in 1977, 178 179 and Newark, New Jersey, in
1972-1974. " 6 The relatively high concentrations of the aldehydes
observed in Los Angeles some years ago in 1968 are not observed
today. More typical are those shown in Figures 5-3 and 5-4. The
diurnal variations observed reflect the meteorologic influence of air
transport and mixing, as well as the other chemical and physical
processes that form and remove these compounds. Table 5-1 summarizes
additional analytic data for total aldehydes, formaldehyde, and
acrolein as determined by chemical methods and reported in studies
made in several large metropolitan areas. The data from the first
four studies shown were obtained in the Los Angeles area and are based
on averages of hourly samples taken only during the daylight hours.
Data from the other studies shown are from annual averages of samples
taken once each 24 h during the year. From these data and the more
extensive data from urban centers in 26 states and

Washington, D.C., 168 it appears that the 24-h average concentration
of total aldehydes is frequently above 0.1 ppm (12 yg/m ) in many
urban areas, but with wide variations; hourly daytime averages may be
near 0.05 ppm (60 yg/in 3 ) and infrequently above 0.1 ppm (120
yg/m 3 ) .

The chemical nature of the mixture of aldehydes present in outdoor
air is expected to be a function of the local emission sources and the
meteorologic factors (sunlight intensity and wavelength distribution,
temperature, etc.) near the sampling site. However, formaldehyde
usually makes up some 30-75% of the total aldehyde observed in ambient
urban air. The complete molecular speciation and composition are not
now available for the fraction of the ambient-air samples determined
to be "total aldehydes" by chemical methods, but all the normal
aliphatic aldehydes containing 1-12 carbon atoms, the 14-carbon
aldehyde, and a few of the common branched-chain aldehydes have been
identified in ambient air. 73 Nine difunctional aldehydic compounds
(Cc-, Cg-, and Cy-dialdehydes, hydroxyaldehydes , and aldehydic
acids) have been detected in aerosols. A study carried out in
California in 1972 included analysis for acetaldehyde, as well as
formaldehyde. 33 Daily averages of formaldehyde were around 0.035
ppm; those for acetaldehyde, the only other aldehyde identified, were
about 0.02 ppm.

Although Graedel 73 reported that only one of the aromatic
aldehydes had been detected in ambient air (4-methylbenzaldehyde, at
50-280 ppt) , benzaldehyde and 2-methylbenzaldehyde ,
3-methylbenzaldehyde, and 4-raethylbenzaldehyde probably are also
present in at least minute amounts. Such a conclusion is based on two
types of information: first, the latter aromatic aldehydes have been
detected in the emission of automobiles burning gasolines that contain
aromatic hydrocarbons (as is discussed in more detail later); second,
on the basis of photooxidation investigations with toluene and xylenes
(common ingredients of gasoline), such aldehydes are formed. 57 If
the aromatic-hydrocarbon content of gasoline increases, the amounts of
aromatic aldehydes present in the atmosphere will probably also
increase.

CTj CO

C T)
H Q

; ?>

r **

J-J

0) -""N

CO U

cS

43

OH
CXti

-HCU
*-" >

- ? "<
C J-i

H 4J
0) B

I-H QJ QJ

O U M

Mflr3
U O 0}

f3 cU
O >
'H<

OO
I

o

ON
CN

__

en

.

CM
x-/

oo

CO

cn

43
CO

en

43
CO

en

III
II I

cO
4J
O

H

l-l CO

0) C

TJ O

d -H

3 4-1

CO

tO -H

cu >

co
4J
CO QJ

co P

rH CO

4J CO

4J 0)

42

4J 4J

& c2
cu cu

U M

x co

QJ Qu

... 3

4J rH

O r-i

-H O

H P-i
4J

* en co

C -H 4J

o Q o

4J (0

rH i I 0)

-H O d

f2 S
O

O B

O

f3 )j

o M-I

H 4J co

3 3 u
o-Hcd

O rH -3
O

o PI co

-H 4J

43 ~J O

O -H CD

fl 3 a,

4J O 3

CO -H H

Q 43 S

o

>

4J 4-> fi

H w o

rH QJ 4J

tO S CO

W

>>H

,3^-1
(DO

,

ool

BUM

MC(3
OOcd

TI

43CU

fXM

O.eO

M

QJ-QJ
Tjt2>
>,O<3

CO O 60

4J a a

O O cd

EH O M

|

o

O
CO

o

CO

o

o
m

rH
I

oo
CO

o

m

oo
CM

H
CO

o

^
I

o

II!

i i i

in co

00

H rH

<! o
-a

>, . 4J U

$ s -g 5

MD-OrH-H?

agucoo
-HtocirJC

r-iCOOH-HO
34JbpU>H
-d 43 -rf u
I 0) M iM O
<U-*iHOOa

O-HM-HO*
COcfl>4-lUO>>
4JCO>4J

IJ-J

i

42

o

c i-i co a i-i o

fl tfl 4J

OJ (U M C

-

QJ O<
M CD

cu

4-1

co

a

tn

H

O rH

i
m

CM

CM
CM

00

00 i-l
vO

CO

CM
00

00
vO
CTi

-d-
r*.
o\

m

^ ^ 5 S a S>

CUediHrHO<;

U 4J J-l 4J H

O rt tU 3 M-i H

O T3 T3 CQ O

CO H

CO 4J 4J
CO

TJ O

QJ >^ CO T3 O O
p> 43 TJ S CO

H Q) -H O C CO fl

QJ X O

0) QJ 4-1 4J CO (2
TJ T3 4J fl

OJ rH (0 43 rH Q)

Q < > O

H 4J

43

44

Acrolein, the simplest unsaturated aldehyde, is of special
interest, because of its effectiveness in inducing eye irritation and
its general high toxicity. It appears to constitute a small but
important fraction of the aldehydes in the urban atmosphere. Table
5-1 shows that the average acrolein concentration is 8-26% of the
average formaldehyde concentration. Scientists in Tokyo have reported
an average acrolein concentration of 7.2 ppb (0.0072 ppm) , which is
within the range shown in Table 5-1. 98a

In summary, the present data suggest that in a clean, unpolluted
atmosphere aldehyde concentrations at ground level are commonly about
0.0005-0.002 ppm. In polluted urban ambient air, the concentrations
are much higher commonly an hourly average of 0.01-0.05 ppm during
the daylight hours. Formaldehyde is the dominant aldehyde present,
and it usually makes up 30-75% of the total aldehyde present. Limited
analytic data show that acetaldehyde may be present at about 60% of
the formaldehyde concentration, and the higher aliphatic aldehydes are
present at lower concentrations, decreasing rapidly with increasing
molecular weight. Acrolein may be present at about 10-25% of the
formaldehyde concentration; the aromatic aldehydes appear to make up
only a few percent of the total aldehyde. Other dialdehydes or
difunctional aldehydes presumably contribute to the aerosol mass in
which they have been observed.

There is now no quantitative rationale that we can invoke to
explain the large day-to-day or even year-to-year variations in
aldehyde and hydrocarbon concentrations in the atmosphere.
Experimental evidence from Houston, for example, obtained from 1973
through 1975 are most interesting in this regard. In some cases, the
aldehyde concentrations were found to vary by a factor of 5-10 within
several days. In one extreme variation, a reading of 52 yg/m
(0.042 ppm) occurred a week after and a week before readings of 6-7
jjg/ra 3 (0.005-0.006 ppm). In 1973, aldehyde values in Houston
averaged higher than those in 1975 and especially those in 1974. No
explanation was given for such differences. Atmospheric conditions
must be responsible at least in part for day-to-day and year-to-year
differences. The following are some of the factors that appear to be
important in this variability:

Wind conditions, including velocity and direction, strongly
affect the dispersion of emission.

Rain, standing water, or moist surfaces can be important
sinks for formaldehyde.

The extent of cloud cover and the position of the sun affect
the sunlight intensity, which alters the rate of photochemical
reactions.

Air temperature affects the rate of chemical processes.

Time of year may be important relative to atmospheric
aldehyde concentrations; this is in part a result of temperature
inversions that entrap the emission in the atmosphere near ground
level. July through September, in general, had the highest
concentrations in New Jersey, 1 * 6 Cincinnati, 93 and Houston. 93

45

\ direct comparison can be made between the ambient aldehyde
entrations in and near Houston and Cincinnati from 1973 through
and between the concentrations in these two cities and St. Paul,
esota, in 1974. 93 The mean aldehyde concentrations in
innati and St. Paul were in general slightly higher than those in
ton. These results and a detailed analysis of the Houston data
est that the major refineries and chemical complexes of the
ton area do not contribute directly to the aldehyde
entrations. Bay town, in the Houston area, is the home of major
ning and chemical plants; yet it had one of the lowest aldehyde
.entrations in the entire Houston area. This may result in part
i the time required for the conversion of hydrocarbons, perhaps the
>r impurity derived from the Bay town industry, to aldehydes through
jspheric reactions.

In 1973, the aldehyde concentrations in the Deer Park area of
ston were very high rather consistently aoove those in any
ghboring areas. There are several major refineries and
cochemical plants in this area. In 1974 and in 1975, aldehyde
centrations in Deer Park were similar to those in the remainder of
Houston area. The reason for the large reduction in 1974 and 1975
unknown .

Aldehyde concentrations at or near Houston's and Cincinnati's
or airports were similar to those in neighboring areas,
'sumably, airports and planes contribute only a small fraction of
> direct emission of aldehyde in metropolitan areas.

It is clear that transport of the air masses, the height of the
:ing layer, and other meteorologic factors can be important in
:ermining ambient aldehyde concentrations.

3 WORKPLACE

Workers in plants producing plywood or particleboard often use
ea-f ormaldehyde , phenol-formaldehyde, or melamine-formaldehyde
sins. Formaldehyde concentrations in several such plants have been
ported 21 66 82 177 193 and may be as high as 10 ppm. The
>rmaldehyde concentrations in the air in these plants obviously
pend on the ventilating systems. Other key variables include the
lount of free formaldehyde in the resin, the moisture content of the
>od, the humidity of the air in the plant, and the processing
jmperatures. With current emission control technology, formaldehyde
mcentrations are or can be substantially lower.

Workers in a variety of other occupations are also exposed to
>rmaldehyde , as shown in Table 5-2.

ONOCCUPATIONAL INDOOR AIR

The infiltration of outdoor air is one source of aldehydes in the
ndoor environment, but the primary sources are building materials,
ombustion appliances, tobacco smoke, and a large variety of consumer

46

TABLE 5-2
Formaldehyde Measurements in Occupational Environments

Sampling Site

161

Textile plants

22
Garment factory

Clothing store

128

Smog chamber

155

Laminating plants

102
Funeral homes

64

Concentration, ppm
Range Mean

0-2.7
0.9-2.7

0.9-3.3
0.01-unk
0.04-10.9
0.09-5.26

0.68

0.25-1.39

Method of Analysis

Sodium bisulfite,

iodometric titration

Collection in sodium
bisulfite solution

MBTH bubblers
Chromotropic acid
Chromotropic acid
Chromotropic acid

47

products. Aldehydes can build up in buildings with greater insulation
and tighter thermal containment intended to reduce infiltration (air
exchange) and energy consumption.

Measurements of aldehydes in the indoor environment have typically
focused on formaldehyde, whose indoor concentrations generally exceed
those outdoors. Indoor monitoring data for U.S. homes are few, but
limited monitoring data do exist for European homes, particularly in
the Nordic countries. Table 5-3 summarizes the data that were
recently described in detail by Suta. * 7 **

Several studies have concentrated on indoor formaldehyde emission
from particleboard and plywood furnishings in houses. Measurements in
Denmark, 9 Sweden (T. Lindvall and J. Sindell, personal
communication), West Germany (Deimel; 51 * B. Seifert, personal
communication; Weber-Tschopp et_ al_. 19 ), and the United States (P. A.
Breysse, personal communication) have shown that indoor concentrations
often exceed 0.1 ppm and in some cases even exceed the 8-hr
time-weighted average of 3 ppm for workroom air. 182 18S In 23
Danish houses, the average formaldehyde concentration was 620
Vig/nP (about 0.5 ppm), and the range was 80-2,240 yg/nr (about
0.07-1.9 ppm) . 9

Over the last several years, complaints about indoor air quality
have come from residents of mobile homes (constructed with
formaldehyde-containing indoor plywood and particleboard) . Since
1978, the U.S. Consumer Product Safety Commission (CPSC) has received
hundreds of such complaints. Other federal agencies have also
reported an increased number of complaints. In addition, dozens of
lawsuits have been filed against UF-foam manufacturers and installers
and mobile-home builders. It has been estimated that one of every 20
Americans perhaps 11 million people live in mobile homes that
contain substantial quantities of particleboard, plywood, or both and
are therefore potentially at risk of being exposed to formaldehyde.
Thousands more live in homes insulated with UF foam. In August 1979,
the CPSC issued two consumer advisories on UF insulation, citing
possible health problems associated with this type of insulation.

As a result of occupants' complaints, formaldehyde was measured in
more than 200 mobile homes in the United States; the concentrations
reported ranged from 0.03 to 2.4 ppm (about 37-2,940 ug/m 3 )
(Breysse, personal communication) . A study of formaldehyde emission
in new office trailers with air-exchange rates as low as 0.16 air
change per hour (ach) found formaldehyde concentrations in the range
of 0.15 to 0.20 ppm, 60 in contrast with outdoor concentrations of
less than 0.01 ppm.

Formaldehyde vapors are a concern in mobile homes, not only
because the building materials used in their construction typically
contain formaldehyde, but also because mobile homes are more tightly
constructed than conventional homes and thus have less ventilation.

Aldehydes (measured by the MBTH method) were monitored in a study
of 19 homes across the United States. 135 Outdoor concentrations
were consistently lower than indoor concentrations typically by a
factor of 6 and quite often by an order of magnitude. Figure 5-5 is
an illustration of the data collected in this study. The observed

48

TABLE 5-3
Summary of Aldehyde Measurements in Nonoccupational Indoor Environments

Sampling Site

8

Danish residences

Netherlands residence
built without form-
aldehyde-releasing
materials

Residences in Denmark,
Netherlands, and
Federal Republic of
Germany

Two mobile homes in
Pittsburgh, Pa. 135

Sample residence in
Pittsburgh, Pa. 135

Mobile homes register-
ing complaints in

26

state of Washington

Mobile homes register-
ing complaints in
Minnesota 67

Mobile homes register-
ing complaints in
Wisconsin

Public buildings and
energy-efficient
homes (occupied and
unoccupied)

Concentration, ppm

Range

1.8 (peak)

0.08 (peak)

2.3 (peak)
0.1-0.8 b

0-1.77

0-3.0

0.02-4.2

0-0.21
0-0. 23 b

Mean

0.03

0.4

0.36

0.5 (peak) b 0.15

0.4

0.88

Method of Analysis

Unspecified

Unspecified

Unspecified

MBTH bubblers

MBTH bubblers

0.1-0.44 Chromotropic acid

(single impinger)

Chromotropic acid
(30-min sample)

Chromotropic acid

Pararosaniline and
Chromotropic acid

MBTH bubblers

a Formaldehyde, unless otherwise indicated.
b Total aliphatic aldehydes.

"M. Woodbury, personal communication.

0)
CO

I

rH

cd

t-l
O

O

H

Pi '

H

O

H
4-1

H
O

I

in

g

t-

c=

49

50

outdoor aldehyde concentration remained below 25 yg/m 3 (0.02 ppm)
at all times. The study determined that its field sample comprised
two distinct classes of residences: those with high and those with
low aldehyde concentrations (see Table 5-4). In all cases, however,
indoor aldehyde concentrations exceeded outdoor. Although the source
strengths were not determined in this study, the highest
concentrations were observed in the mobile homes, and the plywood and
particleboard generally appeared to be the primary source.

In a more recent study, formaldehyde and total aliphatic aldehydes
(formaldehyde plus other aliphatic aldehydes) were measured at several
energy-efficient research houses at various locations in the United
States. 111 * At low infiltration rates (<0.3 ach) , indoor
formaldehyde concentrations often exceeded 0.1 ppm (123 yg/nr) ,
whereas outdoor concentrations typically remained at 0.016 ppm
(20 yg/m 3 ) or less. Normal air-exchange rates are about
0.75/ach. Figure 5-6 is a histogram showing the frequency of
occurrence of formaldehyde and total aliphatic aldehyde concentrations
measured at an energy-efficient house with an average of 0.2 ach.
Data taken at an energy-efficient house in Mission Viejo, California,
are shown in Table 5-5. As shown, when the house did not contain
furniture, formaldehyde concentration was 80 yg/m 3 ; when furniture
was added, formaldehyde almost tripled. A further increase was noted
when the house was occupied, very likely because of such activities as
cooking with gas. When occupants opened windows to increase
ventilation, the formaldehyde concentration decreased substantially.
Although high, aldehyde concentrations observed in most of the
energy-efficient dwellings that have been monitored were generally
below 200 ug/m 3 .

Indoor and outdoor formaldehyde/aldehyde concentrations were found
to be about the same at a public school in Columbus, Ohio, and a large
medical center in Long Beach, California, and were well below 0.1 ppm
(120 yg/m 3 ) . Both buildings have high ventilation rates, and that
is probably why the indoor concentrations were low and essentially
equivalent to outdoor concentrations.

Because many of the data reported from these field-monitor ing
studies involved houses whose occupants had complained of indoor air
quality, these findings may not be representative of all homes.
However, when data from the Washington sample, which was random, are
compared with those from the mobile-home sample, which was based on
occupant complaints, most of the differences in aldehyde concentration
can be explained by differences in the age of the home. The mobile
homes in the complaint sample are much newer than those in the random
sample. Moreover, when Tabershaw ^t al. 1 ?s analyzed the complaint
data on mobile homes in Washington, it was found that there was no
valid relationship between the degree of symptoms reported by
occupants and the concentrations of formaldehyde and that, regardless
of the actual exposure, all persons in the mobile-home sample reacted
in substantially the same manner. Tabershaw Associates suggested
that, because the study received substantial press coverage in
Washington and other parts of the country, publicity may have

51

TABLE 5-4

Statistical Summary of Aldehyde Concentrations in Various Residential
Structures (Outdoor Concentrations Very Low) a

.ocation and Type of
esidence

)enver conventional
Chicago experimental T
Chicago experimental II
3 ittsburgh mobile home 1
Pittsburgh mobile home 2

Washington conventional I
Baltimore conventional II
Washington experimental I
Baltimore experimental I
Baltimore experimental II
Pittsburgh low-rise 1
Pittsburgh high-rise 1
Chicago conventional I
Chicago conventional II
Pittsburgh low-rise 2
Baltimore conventional I
Pittsburgh high-rise 2
Pittsburgh high-rise 3
Pittsburgh low-rise 2

Observed Range of 4-h
Concentrations, jug/m

87-615
140-300
242-555
200-938
136-934

21-153
34-150
10-285
17-162
6-122
51-152
22-120
20-190
10-159
35-149
10-300
76-240
65-234
20-102

14-Day Monitoring Peril

Mean Con-

Standard

centration,
jag/m 3

Deviatio
>ig/nr

250

118

200

38

325

70

470

167

387

159

52

31

75

25

90

78

78

38

48

20

91

34

56

18

54

29

47

23

78

29

144

75

125

27

149

40

110

32

a Reprinted from Moschandreas et al.

5-16

52

C a -

93 B

5

g -

Si

Outdoor
HCHO-

^ Outdoor
! aldehydes

Indoor-
HCHO

ru~

ro

! Wndoor
I f aldehydes

_n

240

Concentration

FIGURE 5-6 Histogram showing frequency of occurrence of
formaldehyde and total aliphatic aldehydes at an energy-
efficient house with 0.2 ach. Single-family house,
Maryland. Reprinted with permission from Lin et al.

m
I
m

co
cuu

to >f

4= 4=

ex cu

H T3

< < >-?

CO E

V-i bQ

O 3,

r T| x^

g,

C. (U
S B

CO -H

W E-

co

4J

C

M-l CU

B
CU

CU 3
43 CO

1 CO

+ 1
O

+ 1

ON

CM

ON
CM

co

r-

+ 1
o

20

r-.

+ 1
en

CM
CM

O
rH

+ 1

CO

+ 1

o

4-1

CU 4->
H 3

5
U 4-
O H

o

4J
H

" C

^ Lj

CU 3

tH *4-l

CX
3 4=

O 4J

O -H

O 3

C3

CU
H
CX

3

o

o

cu

4-1

4=

T3
CU

H

ex

o
o
o

to

t-l

4.)

CU

C

-a

-a

cu

H

c

CO

to

c

4-1

o

3

4=

o

O

fO

cu

i l

^

CO
4J

o

o

cu

to

4=

rH

>^

4-1

!^j

cu

^,

O

rH

4J

to

cd

43

1

CU

I-l

ex

O

00

ex

14-1

o

14-1

rH

o

o

4J

rH

C

CO

tO

4J

Ns

e

H

^

cu

"4-1

^ J

-O

CO

rH

CO

TI

00

s

- J

H 3

^1

00

*rt

CO

col

3,

cr

cu

(U

O

4J

CM

CO

to

rH

to

}-l

H

*~^

a

cu

CU

t3

cu

oo

O

CO

P

O

CO

CO

rH

4-)

cu

4=

rH

cu

j-i

O

O

e

ex

^

33

X

CU

cu

M

H

91

. H

M

T3

43 fO

H

O

O

C

CO

5 .

CU

O

CO

euro

~-l" S

H

O

S 3

H

CO

Jj

^,

O 4J

CO

(0

33 00

H

e

1-1

tO

a

PQ
S

y -s

s.

00

CM

M V

s ti

cm

C

tO CO

4=

H e

H CO

r-l Cl-

4J

to -*.

CO C

i-l

3 00

3

CU C

3

cu o

H
T3 4J

cu to

00 CU

c a
to o

<U

C rH

C ^

r!

cu

4J

H V

H 4J

O CO

rH

C

H

C co

E C
C CU

cu o

8

M

cu G

CU U

H

4-1 O

4J C

P C

J_i

CU

CU -H

cu o

H vH

cd

OS

4J

a o

^

CO

43

u

rrj CU

53

54

motivated people with health problems, some of which were perhaps
unrelated to formaldehyde, to call on the University of Washington to
make an investigation.

Foreign houses (particularly Danish and Swedish) monitored for
formaldehyde appear to have much higher concentrations than U.S.
houses. These findings probably reflect differences in house
construction and, hence, cannot be considered as representative of
U.S. houses .

Although use of the Danish studies may not be appropriate for U.S.
homes, the treatment of Andersen ejt al_. 9 illustrates the many
variables with which one must oe concerned. He formulated a
mathematical model that estimates the indoor air concentration of
formaldehyde. In climate-chamber experiments, Andersen et al. 9
found the equilibrium concentration of formaldehyde from particleboard
to be related to temperature, water-vapor concentration in the air,
ventilation, and the amount of particleboard present. From this work,
a mathematical model was established for room air concentration of
formaldehyde.

When the mathematical formulation was applied to the room-sampling
results, a correlation coefficient of 0.33 was found between the
observed and predicted concentration not a particularly good
predictive ability. The authors then modified the value for the
adjustable constants by calculating them for each room on the basis of
monitoring results. The modified values led to a correlation
coefficient of 0.88 a considerable improvement in predictability.

Formaldehyde release from interior particleboard occurs at a
decreasing rate with an increase in product age. Eventually, the rate
of formaldehyde evolution decreases to an imperceptible point. The
length of time necessary for the phenomenon to occur (several years)
depends on the atmospheric conditions to which the board has been
subjected, as well as the degree of cure of the resin. The more
unstable groups degrade first, and then the more stable free methylol
groups. lo l

Field tests and a mathematical model were used in 1977 to
determine the half-life of formaldehyde in particleboard typically
used in Scandinavian home construction; it was about 2 yr when the
ventilation rate in the home was 0.3 ach (C.D. Hollowell, personal
communication). Suta 171 * has analyzed the effect of home age on
formaldehyde concentrations in Danish houses. The study indicated that
the half-life of formaldehyde may be much longer than 2 yr. These
data give the following relationship of formaldehyde concentration as
a function of house age when no corrections are made for other
pertinent factors, such as the amount of particleboard in the home,
temperature, humidity, or ventilation: C = 0.50e~' 012A , where C is
formaldehyde concentration, in parts per million, and A is home age,
in months. On the basis of this formula, the half-life of
formaldehyde emission is 58 mo. The difference between half-life
values derived from the test data and those from house-monitoring may
result partly from the fact that particleboard is often added to older
homes for repair and improvement.

Monitoring data for the 65 randomly selected mobile homes in
Wisconsin show a similar decrease 'in formaldehyde concentration with

55

increasing home age. The reported formaldehyde half-life was 69 mo,
which is quite similar to that found in the Denmark study. Monitoring
data on 45 complained-about mobile homes in Wisconsin also showed a
decrease in formaldehyde concentration with increase in house age; the
indicated half-life in this sample was 28 mo. When these data are
combined, the formaldehyde half-life is 53 mo, or approximately 4.4 yr.

Not all residences are expected to have the same formaldehyde
concentration. As suggested earlier, variation occurs even in homes
of the same age, depending on the amount and type of particleboard and
UF-foam insulation used in the construction, as well as on
temperature, humidity, and ventilation. For this reason, monitored
concentrations from a sample of similar homes will be characterized by
a frequency distribution that can be approximated by a known
statistical distribution, which, in turn, can be used to estimate the
range of human exposures to formaldehyde in the residential
environment.

The average ambient formaldehyde concentration appears to be
approximately 0.4 ppm (490 pg/m^) in both mobile homes and
UF-foam- insulated homes. Few data are available on conventional houses
that do not contain UF-foam insulation or that were not designed to be
energy-efficient. The average formaldehyde concentration in
conventional houses appears to range from 0.01 to 0.1 ppm (12 to 120
jjg/m^) and may be only slightly higher than outdoor
concentrations. Houses containing larger amounts of particleboard
would fall on the high side of this concentration range, and houses
with no particleboard on the low side.

Average atmospheric formaldehyde concentrations are generally much
lower than 0.1 ppm in U.S. cities, as indicated earlier. Examples of
annual average concentrations are 0.05 ppm in Los Angeles, 6 16e 18
0.004-0.007 ppm in four New Jersey cities, 1 * 6 0.04 ppm in Wisconsin
cities (L. Hanrahan, personal communication), and less than 0.03 ppm
in Raleigh, North Carolina, and Pasadena, California. 79
Formaldehyde concentrations at four Swiss locations ranged from 0.007
to 0.014 ppm; these concentrations are about one-fifth the
corresponding indoor Swiss concentration. 189 In 1951, a mean value
of 0.004 ppm was reported for mainland Europe. ** 3

SURFACE WATERS AND DRINKING WATER

The high solubility of most aldehydes in water results in their
accumulation in natural bodies of water. Sixteen aldehydes that have
been identified in natural bodies of water, the names and locations of
the bodies of water in which they have been found, and their
concentrations are given in Table 5-6. Acrolein is not included,
because it has been found only in surface water to which it was
intentionally introduced.

Nineteen aldehydes that have been identified in drinking water are
listed in Table 5-7. Quantitative information on most of these
aldehydes is unavailable. Some aldehydes in drinking water may be
produced during water treatment. Chloral, which has been identified

56

Aldehyde
Acetaldehyde

Benz aldehyde

Butyraldehyde
Capraldehyde

Caproaldehyde

Caprylaldehyde

Cinnamaldehyde

3 , 5-Di-tert-butyl-4-
hydroxybenzaldehyde

Dichlorobenz aldehyde

Dimethylbenzaldehyde

Enanthaldehyde

Mesitaldehyde

2-Methylpropionaldehyde

Paraldehyde

Undecyl aldehyde

Vanillin

TABLE 5-6
Aldehydes Identified in Surface Water

Body of Water and Location

Mobile River, Ala.

158

Pacolet and Encoree River, So. Car.
Mississippi River, New Orleans, La.

158
59a

Los Angeles River, Los Angeles, Calif
Unspecified river, Netherlands

Wisconsin River, Nekoosa, Wis.

Glatt River, Switzerland 72
Unspecified reservoir, Netherlands

Unspecified reservoir, Netherlands
Unspecified reservoir, Netherlands
Unspecified reservoir, Netherlands
Unspecified river, Netherlands

Unspecified river, Netherlands"
Unspecified reservoir, Netherlands'
Unspecified reservoir, Netherlands
Holston River, Kingsport, Tenn. c
Delaware River, Torresdale, Pa. 59a

59a

Lake Zurich, Switzerland

62

Unspecified reservoir, Netherlands

62
Lake Superior, Ontario, Canada

Concentration,

NR
NR
12

1
0.3

NR
0.1

0.03
0.03
0.03
0.1

0.03

0.1

0.1

3

1

NR
0.03

NR

1 NR, not reported.

3 G. J. Piet, personal communication.

"H. Boyle, personal communication.

Aldehyde
Acetaldehyde

Benzaldehyde

Butyr aldehyde
Caproaldehyde
Chloral

57

TABLE 5-7
Aldehydes Identified in Drinking Water

Location of Water Plant

47

Cinnamalde hyde
Crotonaldehyde
Dimethylbenzaldehyde
Enanthaldehyde
2-Ethyl but yr aldehyde

Fur aldehyde
Isobutyr aldehyde

Cincinnati, Ohio
Miami, Fla.
Ottumwa, Iowa
Philadelphia, Pa,

100

Seattle, Wash.
Durham, No. Car.

126

New Orleans, La. 100
Grand Forks, No. Dak.
New York, N.Y. 183
Voorburg, Netherlands

183

Voorburg, Netherlands
Voorburg, Netherlands

Cincinnati, Ohio 100
Grand Forks, No. Dak.
Philadelphia, Pa. 100
Seattle, Wash. 10 ?
New York, N.Y. 100
Terrebonne Parish,
Kansas City, Kans.

Voorburg, Netherlands
Unspecified 158
Voorburg, Netherlands

i

Voorburg, Netherlands

New York, N.Y. 100
Grand Forks, No, Dak.
Lawrence, Mass.
Terrebonne Parish, La.

Chicago, Ill. 59a
Prague, Czechoslovakia

158

100

100

100

100

144

Concentration,

NR

NR

NR

0.1

0.1

NR

0.03
NR
NR
0.3

0.1
0.03

2

0.01

5

3.5

0.02

1

NR

0.005-0.03
NR

0.03-0.1
0.03

0.05
0.02
0.04
0.01

2
0.13

58

Aldehyde

I sovaler aldehyde

Methacrolein
2-Methylpropionaldehyde

3-Methylvaleraldehyde

Paraldehyde

Propionaldehyde

TABLE 5-7 (continued)

Location of Water Plant
.47

Cincinnati, Ohio
Miami, Fla. 47
Ottumwa, Iowa
Philadelphia, Pa,
Seattle, Wash. 47
Durham, No. Car.
New Orleans, La.

Unspecified 158

Cincinnati, Ohio
Miami, Fla. 47
Ottumwa, Iowa
Philadelphia, Pa
Seattle, Wash. 47
Durham, No. Car.

Ottumwa, Iowa 100

47

47
184

47

47

126

Zurich, Switzerland
.47

75

Cincinnati, Ohio
Miami, Fla. 47
Ottumwa, Iowa
Philadelphia,
Seattle, Wash.
Durham, No. Car.

47

126

Valeraldehyde

Ottumwa, Iowa

100

Concentration

NR
NR
NR
NR
NR
NR
NR

NR

NR
NR
NR
NR
NR
NR

1
NR

NR
NR
NR
NR
NR
NR

0.5

NR, not reported

. J. Piet, personal communication.

59

in the drinking water of seven U.S. cities, is thought to be formed
during chlorination for water purification. 100

SOURCES OF DIRECT EMISSION OP ALDEHYDES IN AMBIENT AIR
INDUSTRIAL OPERATIONS
Aldehyde Manufacturing Plants

The leakage of aldehydes into the atmosphere may occur in the
operation of industrial plants that manufacture the aldehydes.
Morris ^ 3 1** and Lovell 8 have estimated formaldehyde losses to
the environment to be 0.4 g/1,000 g of product formed in solution.
The atmospheric emission of formaldehyde from manufacturing processes
in the United States can be roughly estimated at about 6 x 10
Ib/yr. These losses usually occur at the following locations within
the plants:

The vent stream from the water absorber used for the recove
of formaldehyde and methanol usually contains carbon dioxide, carbon
monoxide, hydrogen, water vapor, nitrogen (if air is used), and trac
amounts of formaldehyde, methanol, and some byproducts. The absorbe
can be built and operated to recover formaldehyde so effectively tha
the exit gas stream is sometimes exhausted directly into the
atmosphere. Other formaldehyde producers use slightly less efficien
and cheaper absorbers with lower operating costs and use the exhaust
streams as supplemental fuel in the furnaces of their power stations
because the streams often have appreciable fuel values. In another
alternative, the vent stream from the absorber can be sent to a
flare. Almost complete oxidation of formaldehyde, methanol, and
carbon monoxide occurs in both a furnace and a flare, so the exhaust
gas stream from the formaldehyde unit contains little formaldehyde.

The vent stream from the top of the product fractionator us
to prepare specification-grade product solution can be sent as neede
to a flare, a furnace, or an absorber to reduce the formaldehyde
content.

Intermittent gaseous emission that occurs during plant
startup or shutdown is sometimes sent to a flare, the furnace, or a
small water absorber to reduce the formaldehyde content.

Intermittent losses that occur at pump seals, from storage
tanks, or at valves are sometimes controlled with portable gas blowe
used in connection with small absorbers.

Each industrial plant uses various combinations of water
absorbers, flares, furnaces, and catalytic incinerators to maintain
formaldehyde concentrations in the ambient air of the plant at less
than 3 ppm as the time-weighted average for an 8-h workshift. This
the maximal permissible concentration set by the Occupational Safety
and Health Administration in 1979. The EPA does not have an ambient
air standard for formaldehyde.

60

Information on emission from industrial plants producing the
higher aldehydes is very limited. It is probably reasonable to assume
^that the percentages of the more volatile aldehydes such as
acetaldehyde/ acrolein, and propionaldehyde lost into the atmosphere
are comparable with those reported for formaldehyde.

Other Industrial Sources

Shackleford and Keith 158 have reported that aldehydes occur in
the effluent water streams from several types of industrial plants.
Formaldehyde, acetaldehyde, acrolein, paraldehyde, sorbaldehyde, and
syringaldehyde have been detected in unidentified chemical plants in
rather scattered areas of this country. Aldehydes identified in the
effluent from some sewage plants include acetaldehyde, benzaldehyde,
crotonaldehyde , isovaler aldehyde, 2-methylpropionaldehyde, and
salicylaldehyde. It is not known whether the aldehydes in these
sewage plants were produced by microbial or chemical means or were in
the feedstock to the sewage plants derived from various industrial
plants .

Acrolein, anisaldehyde, benzaldehyde, salicylaldehyde,
syringaldehyde, vanillin, and veratr aldehyde have been detected in the
effluent from paper mills. Benzaldehyde has been identified in the
aqueous waste from textile mills. Some of these aldehydes probably
form as a result of reactions involving wood or cellulose.

Fish-culture activities are also a source of formaldehyde in the
aquatic environment. Formalin (aqueous solution of formaldehyde) is
one of the most widely and frequently used chemical agents for
treating fish with fungal or ectoparasitic infections. Treatment
entails exposing the fish to formaldehyde at up to 250 mg/L of
solution in ponds, raceways, or tanks. After use, these formaldehyde
solutions are often discharged into the normal hatchery effluent
stream from both private and government-owned fish hatcheries.

Anisaldehyde has been detected in the aqueous effluent of a pilot
plant being used for coal gasification. This suggests that, when
commercial coal-gasification plants are built, they may contribute to
aldehyde effluent.

Table 5-8 shows reported aldehyde emission from various industrial
sources, as collected by Stahl. 16B

Combustion

Combustion leads to both the direct and the indirect accumulation
of aldehydes in the atmosphere of metropolitan areas. Aldehydes are
present in at least trace amounts in the exhaust gases from
combustion. In addition, there is often, if not always, some unburned
hydrocarbon that escapes to the surroundings. As discussed later,
this hydrocarbon oxidizes rapidly in the atmosphere to form aldehydes
and other oxygenated products. Emission from transportation vehicles,
power plants burning fossil fuels, home and industrial furnaces,

61

TABLE 5-8
Reported Aldehyde Emission from Various Sources 3

Aldehyde Emission
Source __ (as formaldehyde)

Amberglass manufacture

3

Regenerative furnace, gas fired 8,400;ig/m

Brakeshoe debonding

(single-chamber oven) 0.10 Ib/h

Core ovens

Direct gas fired (phenolic resin

binder from oven) 62,400 >ig/ra

Direct gas fired (linseed oil core

binder from afterburner <12,000 >ag/m

Indirect electric (linseed oil core

binder from oven) 189,600 jig/m

(from afterburner) <22,800

Insulated wire reclaiming, covering
Rubber 5/8" o.d.

O

Secondary burner off 126,000 >ig/nr

o

Secondary burner on b,OUU ug/m

Cotton rubber plastic 3/8-5/8" o.d.

Secondary burner off 10,800 to

43,200 jig/in" 3

o

Secondary burner on 4,800 ug/m

Meat smokehouses

Pressure mixing burner

Afterburner inlet 0.04 Ib/h

Afterburner outlet 0.22 Ib/h

62

TABLE 5-8 (continued)

Source

Mineral wool production
Blow chambers
Curing ovens

Catalytic afterburner inlet
Catalytic afterburner outlet
Direct flame afterburner inlet
Direct flame afterburner outlet
Wool coolers
Litho oven inlet
Litho oven outlet
Litho oven outlet
Paint bake oven

Nozzle mixing burner
Afterburner inlet
Afterburner outlet
Atmospheric burner

Catalytic afterburner inlet
Catalytic afterburner outlet
Premix burner

Catalytic afterburner inlet
Catalytic afterburner outlet
Phthalic acid plant

Aldehyde Emission
(as formaldehyde)

109 ug/m 3

1.90 Ib/h
0.90 Ib/h
2.20 Ib/h
0.94 Ib/h
32 ug/m 3
120 Mg/m 3
32,880 ug/m 3
4, 680 ug/m 3

0.19 Ib/h
0.03 Ib/h

0.07 Ib/h
0.31 Ib/h

0.3 to 0.4 Ib/h
0.2 to 0.5 Ib/h
135,600 ug/m 3

63

TABLE 5-8 (continued)

Source

Multijet burner

Afterburner inlet
Afterburner outlet

Meat smokehouse effluent, gas fired
boiler firebox as "afterburner"

Water tube, 426 hp

Afterburner inlet

Afterburner outlet
Water tube, 268 hp

Afterburner inlet

Afterburner outlet
Water tube, 200 hp

Afterburner inlet

Afterburner outlet
Locomotive, 113 hp

Afterburner inlet

Afterburner outlet
HRT, 150 hp

Afterburner inlet

Afterburner outlet
Meat smokehouse exhaust

Gas fired afterburner inlet
Gas fired afterburner outlet
Electrical precipitation system inlet
Electrical precipitation system outlet

Aldehyde Emissic
(as formaldehyde

0.49 Ib/h
0.22 Ib/h

0.22 Ib/h
0.09 Ib/h

0.39 Ib/h
0.40 Ib/h

0.39 Ib/h
0.30 Ib/h

0.03 Ib/h
0.0 Ib/h

0.03 Ib/h
0.18 Ib/h

104,400 ug/
40,200 ug/
88,800 ug/
56,400 ug/

64

TABLE 5-8 (continued)

Source

Phthalic anhydride production unit
(multiple burner)

Afterburner inlet
Afterburner outlet

Reclaiming of electrical windings
(single chamber incinerator)

100 hp generator starter
14 pole pieces
Auto armatures

Auto field coils (multiple
chamber)

Auto field coils afterburner
14 generator pole pieces
Varnish cooking kettles

Four nozzle mixing burner

Afterburner inlet

Afterburner outlet
Inspirator burner

Afterburner inlet

Afterburner outlet
Webb press

Aldehyde Emission
(as formaldehyde)

1.75 Ib/h
0.43 Ib/h

0.08 Ib/h

0.08 Ib/h

0.13 to 0.29 Ib/h

0.49 Ib/h
0.08 Ib/h
0.08 Ib/h

0.30 Ib/h
0.11 Ib/h

0.29 Ib/h
0.02 Ib/h
480 ;ig/m 3
360 pg/m 3
480 ;ig/ni 3
1,920 jig/nT 3

a Reprinted from Stahl. 168

65

garbage fires, and bonfires contributes to the rather high aldehyde
concentrations in metropolitan areas. General reviews of the amounts
and fate of aldehydes in the atmosphere have recently been issued. 115

Transportation Vehicles

Transportation vehicles are important and possibly at times the
predominant contributors to both aldehyde and hydrocarbon emission in
some metropolitan areas. Much valuable information on emission from
automobiles, trucks, buses, airplanes, etc., has accumulated in the
last few years. The exhausts of various automobiles powered with
gasoline engines have been collected by General Motors Corp. Tables
5-9 and 5-10 indicate the relative concentrations of the specific
aldehydes identified in the exhaust gases from automobiles without and
with catalytic converters, respectively. Formaldehyde is almost
always the predominant aldehyde emitted, but at least 11 others have
been identified, including at least three aromatic aldehydes. As
discussed later, the amounts of aromatic aldehydes produced depend
significantly on the aromatic hydrocarbon content of the gasoline used,

Several factors affect aldehyde and unburned-hydrocarbon
concentrations in automotive emission. The most important ones are
discussed below.

Operation of Gasoline Engines and Catalytic Converters.
Automotive manufacturers are under federal mandate to reduce the total
hydrocarbon emission to 0.41 g/mile or less within the next several
years. There is no question but that catalytic converters and other
recent changes in motor-vehicle design and operation have resulted in
substantial reductions in aldehyde and unburned-hydrocarbon emission.
For example, higher air-to-fuel ratios are provided in modern
engines. In 1971, the Los Angeles Air Pollution Control District
(APCD) estimated that motor vehicles contributed about two-thirds of
the total hydrocarbon emission inventories to the atmosphere of the
Los Angeles area. By 1975, with the increased use of catalytic
converters, the Southern California Air Pollution Control District
(formerly the Los Angeles APCD) estimated that motor vehicles
contributed less than half.

Newer cars equipped with catalytic converters often emit aldehydes
at about 20-60 mg/mile; older cars without the more modern control
devices emit aldehydes at about 70-300 mg/mile. Automobiles also emit
a variety of paraffinic, unsaturated, and aromatic hydrocarbons.
Jackson 91 found an average of 2.45 g/mile for 19,70-1974 automobiles
not equipped with catalytic converters. Hydrocarbons are emitted by
1974-1975 cars equipped with three types of catalytic converters at ai
average of 0.48-0.65 g/mile. Recently, Cadle, Nebel, and Williams 32
reported emission rates for catalytic and noncatalytic automobiles
similar to these values.

As more vehicles become equipped with catalytic converters, motor
vehicles will probably emit less aldehyde and unburned hydrocarbon.

The following factors also affect emission:

66

O

O

CO

1-1

cfl

u

4J
CO

Cfl
U

cd
o

4J
CO

3
cti

fl

-n

3

ON

m

JO

m

o

o

O
O

o

CO

JS

-n

XI

<U

a

H

O
CO

cd

o

B
O
H
4J
H
CO
O

B 1

O

aus t

H

CM
CO

30

Q

C!
v, O

C
O
H
4J

cd
1-1

4J
C.3
CU S
O O

m
CM

CO

o

CM

ro

O

O

u

CU

-a

CU

a)

T3

73

CU

>i

>*

T3

cu

X
CU

J3
CU

1

a

-Q

X3

>.

H

H

O

JZ

Cd

cd

CU
13

g

4-1
0)

|

.H

<l

O

En

4!

y

ij

JC

4(

tH
fl
M

>

u

a

og

CU

-o

3

CU

=q

O

t-

o

H

Cu QQ

*J c

O H

E-i >

o

o

H

CU

CJ

e

.

H

o

cd

.

T)

CU

e

CO

o

o

CO

01

a

"d

cd

\-l

H

ed

CU

0)

rH

a

O

CO

3

CO

1-1

A

cd

ed

O

CO
CO

60

C!
H

3

4-J

4J

cu
X

C
CU

C!
CU

O

co

S

CU
IH

M
CU

m

3

4H

4-1

^>

H

H

cd

'"3

o

Q

cd

^

o

"o"

67

TABLE 5-10

Exhaust Aldehyde Composition: Gasoline Exhaust from Catalyst Cars a
Concentration, mole %

Aldehyde

BOM D BOM*-

BOM

Formaldehyde

55

.2

36.

5

35.

1

42.2

63.7

62.

1

78.2

Ace t aldehyde

25

.5

34.

9

40.

8

23.5

14.9

17.

5

13.3

Propionaldehyde

1

.0

3.

6

4.

2

2.4

15.1

2.

6

4.6'

Acrolein

1.

1

ND

ND

0.1

0.

4

ND

Crotonaldehyde

-

-

Methacrolein

4.

1

7.

1

2.4

ND

ND

ND

Benzaldehyde

10

.1

11.

3

7.

5

17.0

3.7

12.

2

2.3

Tolualdehydes

1

.2

2.

3

1.

3

2.2

0.9

2.

3

0.5

Ethyl benzaldehyde

2

.5

3.

2

2.

9

6.0

0.7

0.

6

0.3

Lj j-v tl T f\ \J

4

.5

3.

1.

1

4.3

0.9

2.

3

0.9

9 10

Total

100

100

100

100

100

100

100

Driving Cycle

7 -mode

72-FTP

72 FTP

a j. M. Heuss, personal communication.
Pt mono. oxid. catalyst.
Pt mono. oxid. catalyst; 3 gasolines.
^Dual RO catalysts; same 3 gasolines.
e !975 Plymouth Fury.

68

Age, condition, and degree of tuning or adjustment of the
engine engines require tuning and maintenance, if they are to have
low emission rates.

Converter replacement catalytic converters age and must
eventually be replaced, if they are to maintain sufficiently low
emission rates.

Design of engine engine types in different cars sometimes

result in quite different emission rates.

Temperature of ambient air 75 F was found to result in lower
aldehyde emission for some engines, compared with 25F or 95F; and
starting a cold engine generally results in high aldehyde emission
rates.

Composition of Gasoline or Liquid Fuel. The aromatic-compound
content of gasoline has an important effect on the benzaldehyde
content of the exhaust. 1 2 Little or no benzaldehyde was produced
from a gasoline free of aromatic compounds, but the amount of
benzaldehyde increased linearly with increased aromatic-compound
content. With a 100% aromatic fuel, the ratio of formaldehyde to
benzaldehyde was about 3:1; the total aldehyde content of the exhaust
gases from the engine was, however, nearly constant, regardless of the
aromatic-compound content of the gasoline. Ninomiya and Golovoy 1 " 9
found that rather large amounts of benzaldehyde were produced when
toluene (an aromatic hydrocarbon) was blended into gasoline.

Gasolines produced by different refineries or produced at
different times of the year often contain large variations in the
amounts of specific hydrocarbons. These hydrocarbons may be grouped
into three families: the alkanes (paraffinic hydrocarbons), the
alkenes (olefinic hydrocarbons), and the aromatic hydrocarbons.
Higher-quality or premium gasolines usually have more aromatic
hydrocarbons and/or trimethylpentanes (highly branched Cg alkanes) .
Especially in the recent past, they also generally contained more
antiknock compounds, such as tetraethyl and tetramethyl lead.
Furthermore, winter-grade gasolines as a rule contain more volatile
hydrocarbons, such as butanes, to provide quicker starting. In tests
by Bykowski 29 of gasohol (blends of 90% gasoline and 10% ethanol) ,
summer-grade gasohol for two types of American automobiles emitted
about 50-60% more aldehydes than winter-grade gasohol. The
hydrocarbon composition of the fuel clearly has some effect on the
type and amount of emission, but only preliminary data are available.

Within the last few years, there have been extensive efforts to
develop blends of gasolines that contain various oxygenated
hydrocarbons, including the following:

Ethanol (ethyl alcohol) that is blended with gasoline at
5-20% these blends are generally referred to as gasohol; the main
objective in using ethanol is to develop liquid fuels obtainable from
grains of cellulose-containing materials (such as wood, straw, and
cornstalks) that are grown in this country.

Methanol (methyl alcohol) this has also been tested rather
extensively and is sometimes confused with the gasohol approach;

69

methanol can be obtained from natural gas, petroleum/ coal, and wood;
it is now used as a fuel for some racing vehicles.

Methyl-tert-butyl ether (MTBE) MTBE is being blended with
gasoline at 5-20% by several oil companies; it results in
substantially higher octane ratings and is thought by many persons
knowledgeable about gasoline to have a bright future.

Gasoline and gasohol have been compared in several types of
automobiles, but the results are inconclusive. Bykowski 29 found
lower aldehyde emission rates in one automobile when gasohol was used
but the opposite in another automobile. Chui, Anderson, and Baker 1 * 5
made a rather large number of tests with gasohol blends containing 2G
ethanol in several Brazilian automobiles. There were small but
significant increases in aldehyde emission from ethanol-gasoline
blends when the engines operated at low load. Differences at normal
load, however, were small and perhaps insignificant. A considerable
number of investigations have compared methanol-gasoline blends and
pure gasoline. In general, slightly more aldehyde was emitted from
methanol-containing fuels; 13 * 7 ll>8 some of the increase occurred in
tests at higher compression ratios that simultaneously resulted in
increased engine efficiencies. One of the major advantages of
methanol is that it produces higher octane blends that can be burned
at high compression ratios. It has been suggested 1118 that aldehyde
emission can be markedly reduced by proper adjustment of the
air-to-fuel ratio and by spark-advance settings.

Preliminary information has also been published on the use of
MTBE-gasoline blends. Emission from the burning of such blends is
comparable with that from unblended gasolines, except for somewhat
higher aldehyde and isobutylene emission from the blended fuel. 81
It is thought that emission problems of the blends can be made at
least comparable with those of unblended gasolines by proper engine
adjustment and minor changes in the operation of catalytic convertei

There is need for continued testing of aldehyde emission from
automobiles as the use of gasohol and other new fuel blends increase
although present evidence suggests that proper use of catalytic
converters and other devices may control this emission quite well.

Type of Engine. Several engines have been considered as
alternatives to the conventional piston-cylinder gasoline engine us<
almost exclusively for many years in automobiles. Such engines
include the diesel, stratif ied-charge (PROCO) , and rotary engines,
with the conventional gasoline engine, rather large variations in
performance occur from engine to engine, including aldehyde and oth<
undesirable emission. Such differences are caused by numerous
variables, including engine design and operation, fuel composition .
quality, and use of or failure to use a catalytic converter.
Comparisons of various engines have been conducted by most if not a
major automobile manufacturers and oil companies, universities,
research organizations, and government laboratories.

The following comparisons of diesel and gasoline engines are
applicable:

70

Diesel engines emit more hydrocarbon and aldehyde than
gasoline engines equipped with catalytic converters. They also emit
appreciably more particulate material. The relative importance of
specific hydrocarbons and aldehydes in the emission from diesel
engines tends to be quite different from the relative importance of
those from conventional gasoline engines.

In many cases, the aldehydes emitted from diesel engines have
higher molecular weights than those from gasoline engines.
Isobutyraldehyde is sometimes the most important aldehyde on a weight
basis. 152 1SS Over twice as much isobutyraldehyde as formaldehyde
was emitted from one engine. In another and more typical case,
formaldehyde emission was higher. The increased yield of the higher
aliphatic aldehydes from diesel-fuel combustion probably results from
the dominance of the higher-molecular-weight paraffinic hydrocarbons
in this fuel. Benzaldehyde normally is either not detected in the
emission from diesel engines or present in only small amounts; most
diesel fuels contain little or no aromatic hydrocarbon.

Emission from a stratif ied-charge (PROCO) engine and emission from
a conventional gasoline engine have been compared to at least a
limited extent. In two comparisons, the stratif ied-charge engine
emitted more aldehyde than a regular gasoline engine. 29 125 In two
others, the opposite was reported (Bachman and Kayle; 12 J.M. Heuss,
personal communication) : two Honda CVCC engines emitted considerably
less aldehyde. Insufficient information is available to draw any
generalized conclusions relative to the aldehyde emission of the two
types of gasoline engines.

There are limited data comparing a rotary engine such as was used
at one time in Mazda cars with conventional gasoline engines
(Bykowski; 29 Heuss, personal communication). The rotary engine
emitted more aldehyde than the conventional engines in at least three
comparisons; in two cases, the differences were large.

In summary, we may estimate that direct aldehyde emission from all

O

vehicles in the United States amounts to about 2.6 x 10 Ib/yr.
Another 10 9 Ib/yr is probably generated from the atmospheric
oxidation of the hydrocarbon emitted by these vehicles. These
estimates are very approximate and may be in error by as much as a
factor of 3.*

Other Combustion Processes

Fossil-fueled power plants emit several undesirable materials to
the atmosphere, including aldehydes, as shown in Table 5-11. The

*The following assumptions have been made in deriving these
estimates: 120 x 10 gal of gasoline are consumed per year; travel
amounts to 144 x 10^ miles/yr, with an average gasoline mileage of
12 miles/gal; hydrocarbon is emitted at 0.41 g/mile, as mandated for
the future; and 20% of the emission is aldehydes, and 80%, hydrocarbon.

o o o o o o

o o o

00 O O O O O

SluuxXX X X X

o a o *o *o o o o

XX X

o o

in KI

IM <M

X X X X

O O Kl O

o m o

1 I IM

Sill I I I

O O O O O O

W "x X IS "it *K

p^eatooiv IM M oo

I O CM - 10

X MS

o o
x "x

V CO

a in

u

H

:ion Sources 3

s

S.O i B
-303

2,s i:: "

>< Q. X."o

O a. ja >

u

S/^
IM I- e >n o
iu u o ^ o o a
5 u. o z ev ( *u

Z ^ i en

z *i? u

o c *
eo a e *M w

IM O T

r- o -
o in o

Ol O Kl

<r *r o

1 IM

O

<o

CM

10 IM in o

IM ft O IO

in oo O O
o r* 03 in

IM 1 <M

KI eo fM

00 Ol Kl

o o o
O to in

to

oo

03

IM

Kl

in

IO

O

in

(N

CM

O

f-
o

S3

m *

Kl

IO

Kl

o
o

IM
00 IN

a

O

Kl 1 OO

r- to ^ rM

O m 01 xO
to O O

O

*
oo o r>

4-1

CO 1

rf "5 U H v2

O

o

>*>

_ K)

O 1

o

Kl O

O Z

r*- ^ in

>o

O

O Kl

^

O

10

CM CM VO

CU

a m -J o 3

000

o o o

O f- O

a
a

IM Kl
O

3

o o o

e

o o o

o

o"

o o o o

O'

a o

o

o o o

K

u

V.2 (

uj '

1 00

lA

01

IM

in

Ol CO

*o

a 01 IN

2 a b c * t>

cfl
_cu

a; Q

< 2 X) I B

G Q -i o a

o o ^
o in

t

2

-4 -4 in -^

m

CO
Kl

m
r in

O IN

Kl

o

\o o
O rM CM KI

o o o o

m

5 o>

o o o

o

o"

-i

o o

o

tO

1

V

V

1

1 1 U

i u a i

f. Kl Kl

^

1 _ l

<0 fM

O

^

.

^

e K a > e

a

o

~

o to o

vO

o

o

r-.

00

09

o

U> Kl tO CM

S

e *

M

o o a

H vu

IM

-

-4 Kl

vO

r~ *

O ~4

r^tor,*

c

5 2 2

Ol *O

IM

CO

rM

in T o

CM T CM

S

a in

CM O

oo r

CM

10 O O IM
O

o

Z S3

O rsi -*

O

00"

o

0000

H

^

CO
CO

O

" So

O O Ol

in 01 01

<0

<o

m

<o

< rM o
IM in oo

S

Ol

o

s

o r*
r -a

a

IN

O

SO < r-
IM

o o o o

323

-<

o"

o o

O

o

o o

o

o o o o

aq

<n

M IN

01 i r-

m

^

i r

IN

o

Ol

Kl Kl

IO

o Oi to m
O ^) f* r^

4-1

P!

DQ

K..O-

WO

o

m so co

O

eo

Ol

CO CM

o

Ol V CM O

CO

fro^

00

Kl

in fM CM CM

4J

1

Q Q

-* 1 m*

"*

rH
O
PL|

X

in >o *o

tO

"

IM CM CM

00

""

Kl

rM *+

00

of u.

o in Q

<O Kl KJ

in

o

o

00

in in o

ro ^ rM

O
Kl

v to

o

r

in in
r. ca

o

CO

o o o in

-* ~ Ol

00

IM fM

Kl

IN IO CM

in

to CM

Kl

IM -f ~-t IM

H

.

O

8S8_

o
o

o

s

O Kl 00
Ol V I s -

o

IM

o m
o 01
o -

in

in 01

o

s

in IN IN

IM Ol OO p
Kl

O *5

m CM m

eo

to"

10"

in

10"

u

1 Kl

UU M

u

O I

o

fl

t-

14 1

a

u <s

IS

o

<n

S oo

a -a

H at

l-i U

fc- tl

u

-i IM

M N

u

hi

U "O

U <w

u n

-1 -H

x e

SJ2

Vi <->

a e

j< ra

U

Jrf U

o >

<-l "O

o -a
u e

U M

i*

K u

H e

H U

2 g.

SE
u a

0. U

HI Q,
LO

M e

n of

*-> M
I/)

1

a o
U

a n

u ja

V 41

a

m

u. a

e

3

O

a

CO

4-J
CO
CU

CO

o

H

-o
in

H
CO

s

C0|

4->
(U

U
CO
JQ

G
O
H
CO
CO

1

CU
(X

g

-a
cu

TJ
cu

"O

co

4-1

o

o
o

o

CO

cu

rH
U
H
4-J

CO

a,

71

tx
cu

72

amount and type of such emission vary greatly between plants, but the
lowest rates of formaldehyde emission occurred in some coal-burning
plants. In 1978, Natusch 137 reported rather limited data from power
plants using coal, oil, and natural gas. Coal-fired furnaces emitted
the most particles, the most carbon monoxide, and the least aldehyde
(reported as formaldehyde). Aldehyde emission by coal-, oil-, and
natural-gas-fired furnaces was reported to be 0.002, 0.1, and 0.2 Ib
from 1,000 Ib of fuel. If the results of Natusch are average values
and if the consumption data of the U.S. Department of Energy for coal,
oil, and natural-gas consumption in power plants are used, the amount
of aldehyde emitted from power plants in the United States is
estimated to be approximately 50 million pounds per year (see Table
5-12) . The unburned hydrocarbon emitted may lead to the eventual
formation of 10-20 times more aldehyde. Large changes have occurred
in the last 10-20 yr in the design and operation of fossil-fueled
power plants. As a general rule, the major emphasis has been on
increased energy efficiency. The results probably produce more
complete combustion and decreased aldehyde concentrations, although
specific data to support this hypothesis are not available.

Sulfur dioxide is considered by many to be a more obnoxious
emission from oil- and coal-burning plans than aldehyde. Natusch 137
pointed out that the polycyclic organic materials formed to a small
extent, particularly from coal-fired furnaces, were especially
critical, in that such materials are generally considered to be
carcinogens.

A variety of aldehydes have been identified as products of forest
fires (Table 5-13) . Bonfires and garbage fires also produce aldehydes
and other undesirable byproducts. The amounts emitted obviously
depend on the size of the fire, i.e., the amount of material burned
(Table 5-14) . In most cases, detrimental effects of such fires are
limited to the immediate area of the fire.

The combustion of tobacco in the process of cigarette-smoking also
generates a variety of aldehydes. This is an important source of
aldehydes only in the indoor environment, and it is discussed in more
detail later in this chapter.

VEGETATION

Plants in general have the ability to release volatile compounds
into the air through their stomata and cuticle. Of these compounds,
carbon dioxide, oxygen, and water have been studied in detail, owing
to their metabolic relevance. Attention has recently turned to plants
as a source of hydrocarbons important enough to affect air quality.
Terpene diffused from forest trees has been the principal compound of
concern; 150 aldehydes, in comparison, have received little attention.

There is ample evidence of the natural occurrence of aldehydes in
plants. Schauenstein et^al^. 153 noted that aldehydes are widely
distributed in fruits, imparting a characteristic aroma and flavor to
pineapple, apple, grapefruit, lime, banana, pear, peach, lemon,
blackcurrant, strawberry, orange, grape, and raspberry. Strawberry

W

d

o

4J

f-l

cu

ex

r

H

-H

cd o\ en vo en en

H

o

X)
XI E

o m rH -o o c^

14-1

rH

o

vO

CO O

CU rH

XI

x

4-1

crt * - *

m

hU p^

4-i d cd

ON

co o t-i

H D

'O CO 4J

B <^ rH o

m

cu co cd
4-1 -H 53 C
iH S

id en H vo r^ o\
5 en en CM CM CM

d"

d w

4-1

cu

XI

d -d

H

,

fl oo r>* ^j- vo .

H * -J-

CM

CO 0) r
4-1 -xa C
d rH

cd <J

rH

H rH 00 00 H f>x ^
3 iH rH rH eM rH a

o

o

rH

PM 4-i

En

H .

o

o d

r4 (D r-

o

fl) M c
? -H <

d en in oo c^ rH d

"d w

Q C
P-I

3 rH rH rH H CM -H
CO

O f-i
4-1 <L)

\ a.

a

CO

x>

rj

rH CO

M
4-1

B
o

* W)

o

d

*^5 *l-l

O rH en
H Cd 4.
CO ^14.

co cd 3

H /-> 4-J COCTi
H t3 cd cd C

W CU 12; O r-

co

\ ^.

H CN rH QO ^

en vo oo oo cr\ o

ON vO O rH -* PM

)*.
< en en en en en H

f-l

o
o
en

A 4-J

cd
Oen

o o

CU -H

Cd

rH

rrj *>

f* o

cu

X

X! M

cu d r-

13 3 X

i <U

pTi

CO

cd i ^o

.

3 ^ . x

in CM ON oo m

*n CO
4-1 CM

"8 1 gS

II ^J

in o m ir en oo
en o m en CM M
en in ""> vo in cu

ex
1 d"

CO O

Sa
g

d
M

CO 4J

H 3
4-1 CO

co d cc

8

drH

w o d

4-1

H ^J'

3

C_3 C

rH rH

r*
CM CM st CM 00 0)

rH

CU CtSO
3 O O

O <t 00 H 00 4
C^J 00 -<t 00 CM M

rH f
O CO

ta CJ r-i

en en ~* <) m eo

3)

a

d

0)

rH

Q

cd

cd

o en *> oo o> co

^O lj
CU 3
CO 4-1

cu

w^ ^^ ^^ ^^ ^^ ^^

vy

nq d

^

rH H rH rH H Cd

x

73

74

TABLE 5-13
Aldehydes Emitted by Forest Fires a

Aliphatic
Formaldehyde
Acetaldehyde
Propanal

Aromatic
Vanillin
Conifer aldehyde
Syringaldehyde
Sinapaldehyde

Is o but anal

Olefinic
Acrolein

Cyclic

Furfural

5-Methylfurfural

a l)ata from Graedel. 73

75

TABLE 5-14
Gaseous Emission from Open Burning a

Gaseous Emission, Ib/ton of material
initially present

Test
No.

Material Burned
Municipal refuse

CO,,
1,250

CO

hC b

Formaldehyde
0.095

Organ
Acids'

14

1

90

30

2

1,210

80

30

0.094

16

Avg.

1,230

85

30

0.095

15

3

Landscape refuse

860

80

35

0.005

18

4

550

50

25

0.006

8

Avg.

700

65

30

0.006

13

5

Automobile
components

1,500

125

30

0.030

16

a Reprinted with permission from Gerstle and Keranitz.

Gaseous hydrocarbons expressed as methane.
Expressed as acetic acid.

70

76

and pear have an especially high aldehyde content 13-18 rag/kg. Some
species contain three carbonyl compounds f others as many as 20 (Table
5-15); 2-trans-hexenal (2TH) is the most common. Schauenstein et al.
speculated that the unusually wide distribution of 2TH indicates that
it probably is formed during the processing of the fruit. According
to their interpretation, some aldehyde in apple and fruit ^uices is
formed biogenically in the fruit/ and some of the remainder is
produced by enzymatic and nonenzymatic reactions during processing.
Vegetables are not without their share of aldehydes. 167
Acetaldehyde, propionaldehyde , isobutyraldehyde, and butyraldehyde
have been detected in beans, broccoli, brussels sprout, cabbage,
carrot, cauliflower, celery, cucumber, lettuce, onion, potato , and
soybean .

Woody species also contain aldehydes, but there is disagreement as
to whether they occur in healthy, as well as in injured, tissue.
According to Schauenstein et: a!L. , 153 one report stated that 2TH was
emitted by Robin ia pseudoacacia in the absence of injury when the
plant was enclosed within a plastic bag for 12 h. More numerous
reports cite the capacity for formation of 2TH in injured trees, such
as Ginkgo biloba, Albizia julibrissin, and Ailanthus glandulosa. It
has been suggested that the biosynthesis of aldehydes is a defense
against biologic attack, for example, in the resistance shown by
ginkgo to fungi. 123

In the course of inquiry into the possible etiologic factors of
nasopharyngeal tumors among the Chinese and Kenyans, Gibbard and
Schoenthal 71 made a semiquantitative measurement of sinapylaldehyde
and related aldehydes in the wood of eight angiosperms and two
gymnosperras. The aldehyde content varied according to species, with
Eucalyptus sp. and Fagus sylvatica having the highest and Juniperus
procera and Larix decidua the lowest content (Table 5-16).

There is some information on the location of aldehydes in plant
tissue. 1S3 A report by Lamberton and Redcliffe established that the
long-chain aldehydes occur in cuticular plant waxes. On measuring the
aldehyde content as a percentage of total lipids, they found a range
from 0.2% in purple loosestrife (Lythrum salicaria) to 14.3% in
cranberry (Table 5-17) . Apparently, the distribution pattern of
aldehydes is so characteristic for a species that it may have value in
taxonomic studies.

Aldehydes emanating from vegetation have been detected in ambient
air. 73 Thirty-six plant volatiles including aliphatic, olefinic,
aromatic, and cyclic aldehydes have been cited by Graedel (Table 5-18).

When plant material is burned either deliberately for disposal of
agricultural waste or unintentionally as in forest fires, the increase
in aldehyde emission may become significant. Because the nature of
the plant material and the conditions of the burning can vary widely,
it is difficult to characterize the emission. In a special experiment
with a tower that simulated field conditions, Darley et al. 51
compared emission from the three principal types of agricultural waste
in the San Francisco Bay area. The number of pounds of total
hydrocarbon emitted per ton of plant material was 9.7 for fruit
prunings, 14.5 for barley straw, and 4.4 for native brush. Aldehydes

Pineapple

formaldehyde
acetaldehyde
furfural

Apple

formaldehyde

acetaldehyde

propanal

1-butanal

pentanal

hexanal

2-hexenal

furfural

C 24-30 a l deh y des
Grapefruit

acetaldehyde

citral

C 7_H aldehydes

Lime

octanal

nonanal

citral

dodecanal

furfural

Banana

acetaldehyde

1-pentanal

2-hexenal

C 24 C 26' C 28'

c 29 , c 30 , c 31 ,

C^2 aldehydes
Peach

acetaldehyde
benzaldehyde
furfural

C 24> C 26

C aldehydes

77

TABLE 5-15

Carbonyl Compounds in Various Fruits 3
Pear Orange

acetaldehyde

propanal

2-hexenal

Lemon

heptanal

octanal

nonanal

decanal

undecanal

dodecanal

C^3_17 aldehydes

citral

neral

geranial

citronellal

Blackcurrant

acetaldehyde

butanal

pentanal

hexanal

2-hexenal

benzaldehyde

Strawberry

acetaldehyde

propanal

2-propenal

2-butenal

2-pentenal

hexanal

3-cis-hexenal

heptanal

benzaldehyde

furfural

methylfurf ural

acetaldehyde

pentanal

hexanal

2-hexenal

heptanal

octanal

octenal

nonanal

decanal

undecanal

citral

neral

geranial

dodecanal

01, 6-substituted acroleins

C 24' C 26 ' ^28 C 30
Grape

acetaldehyde

butanal

hexanal

2-hexenal

benzaldehyde

Raspberry

acetaldehyde

propanal

2-propenal

2-methylpropenal

2-pentenal

2-hexenal

3-cis-hexenal

benzaldehyde

furfural

methyl furfural

a 1 ^

Reprinted with permission from Schauenstein et al.

alkenals have 2-trans configuration.

Unless otherwise stated,

78

TABLE 5-16

.a

Yields of Aldehydes in Wood of Various Tree Species'

Aldehyde Yield, ;ig/g

Tree Sinapyl Syringic Coniferyl Vanillin

Eucalyptus sp. J,OOU 3,000 1M) 100

Fagus sylvatica L. (beech) 800 800 250 250

Tectona grandis (teak) 700 500 600 450

Santalum album (sandalwood) 600 500 300 200

Quercus robur L. (oak) 500 600 250 200

Chinese incense 500 600 250 250

Indian incense 100 200 100 5U

Cocos nucifera L. (coconut) 300 500 3UO 300

Juniperus procera Hochst 450 bOO

Larix decidua (larch) bOO bUO

Reprinted with permission from Gibbard and Schoental.^ 1

79

f"** QO ON
04 m

rt 00

6 o

o
S -

ao <N irt

cfl

CO

u

H

IS O

I

LO

-d

fi

C/3

s

H

CO
0)

01
-d

rt o*

m oo

t^

^o n rn oo

OO O

-n

n
H

s Distribution of aldeh]
il

C 3 4 C C M

*

(N

>n

r*

^r

00

TT

6

>*

ON
en

en

>M

'?
O

ON
CS

%^- i^-

ft Tf

VO 00
CN

*
tN

O iS

f 9?

o

^

^

00

10

m

CN

NO

,

^Sj*

Wl

w

~

*

6

rn

O

ON

J

5

O

x- \

^

r\

2

/ N

3

J

>

8

(Axum uttntm)

bane
icynum androsaemifi

an hemp
ycynum cannabuwm

&

1

a

V

>horbia cyparkuas L.

^
X

3

a

J

1

s
1

le loosestrife

*~ \
J

1

E
1

ten {Chenopodtum at

pass (Lolum perenm

^1
SI

cd
J=i
a

V3

^
m

PI
o

H
CO
CO

OJ
Pu

x:

4-1

d
ai

4J

c

H
^
P-

cu
od
cd

80

TABLE 5-18
Aldehydes Emitted from Natural Plant Sources 3

Alipnatic

Formaldehyde

Acetaldehyde

Propanal

i- But anal

Isobutanal

ji-Pentanal

Isopentanal

Hexanal

He pt anal

Octanal

Nonanal

Decanal

Unde canal

Te trade canal

Aromatic

Be nz aldehyde
Cuminaldehyde
Dihydrocuminaldehyde

Phenylpropanal
Cinnamaldenyde
_p_-Hydroxybenzaldehyde
Anisaldehyde
j)-Me thoxycinnamaldehyde
Piperonal
Vanillin
Veratraldehyde
Conifer aldehyde
Eve rnic aldehyde

Olefinic

l-Hexen-2-al

trans-2-Hexenal

3, 7-Dimethyl-2, b-octadien-1-al

3 , 7-Dimethyl-b-octen-l-al

4-Hydroxy- 3 , 7-dimethyl-6-octen-l-al

2, b-Nonaldien-1-al

Cyclic

Furfural
Safranal

a Data from Graedel. 73

\

81

were not mentioned specifically. In the burning of landscape refuse
(lawn clippings, leaves, and tree branches), Gerstle and Kemnitz 70
reported 30 Ib of hydrocarbons and only 0.005 Ib of formaldehyde per
ton of material. Combustion of the same amounts of municipal refuse
and automobile components yielded about the same amount (30 Ib) of
hydrocarbon, but an increase in formaldehyde from 0.005 Ib/ton to
0.095 and 0.030 Ib/ton, respectively.

INDOOR SOURCES OF ALDEHYDES

Aldehydes enter the indoor environment through infiltration of
outdoor air and from a variety of sources within the indoor
environment itself. Indoor sources include aldehyde-containing
building materials, combustion appliances, tobacco smoke, and a large
variety of consumer products. Measurements of aldehydes in the indoor
environment have focused almost exclusively on formaldehyde. In
general, indoor formaldehyde concentrations exceed outdoor
concentrations. The contribution of formaldehyde in outdoor air to
indoor formaldehyde concentration appears to be minor. This section
considers some of the important indoor sources.

Building Materials

The low cost and superior bonding properties of formaldehyde
polymers make them excellent choices as resins for the production of
various building materials, especially plywood and particleboard.
Resins used for building materials include urea-formaldehyde (UF) ,
phenol-formaldehyde, and melamine-formaldehyde.

Urea-formaldehyde resin is the most common adhesive used for the
production of indoor plywood and particleboard. It is also used in
protective coatings and for treating paper and textiles. UF resin
contains some free formaldehyde and decomposes and releases
formaldehyde gas at high temperature and high humidity.

Phenol-formaldehyde resin, which does not release formaldehyde as
readily as UF resin, is used as adhesive for wood products requiring
greater moisture resistance (i.e., outdoor plywood).
Phenol-formaldehyde resin, however, is not generally used for most
indoor wood products, because of its higher cost.

Plywood is composed of several sheets of thin wood glued
together. Particleboard is made by saturating small wood shavings
with a resin (usually UF resin) and pressing the resulting mixture,
usually at a high temperature, into the final form. Particleboard
continuously emits formaldehyde, but at a steadily decreasing rate
over a period of several years; in dwellings where it is used for
furniture, partitions, etc., the emission may become large and even
exceed the OSHA time-weighted average of 3 ppm. The emission rate
varies as a function of several conditions, such as the original
manufacturing process, the nature of the wood used, the quantity of
catalyst used in curing the resin, quality control of fabrication,

82

porosity, humidity, cutting of the board for final use, rate of
infiltration, and ventilation.

The problems with plywood and particleboard are especially severe
in mobile homes. 19 Within the last few years, there has been a
trend to make mobile homes more airtight in an effort to conserve heat
in the winter and minimize cooling demands in the summer. Hence,
there is less turnover of the air in a mobile trailer, and
formaldehyde emission from plywood and particleboard has become much
more obvious and of increased concern. Because air-exchange rates
affect indoor air quality, the rate of release of formaldehyde from
these building products and the air-exchange rates in the design of
mobile homes are especially important for the control of pollution.

Insulation

UP foam is used as thermal insulation in the side walls of
existing buildings, 116 mainly single-family residential buildings.
It is convenient and inexpensive to inject the foam through small
holes that can be sealed after insulation is completed.

Installation involves mixing partially polymerized UF resin with a
surfactant (foaming agent) and an acid catalyst under pressure that
forces air into the mixture to create a foam. The foam hardens within
minutes and cures and dries completely within a few days. Building
codes in the United States, concerned with the fire-safety aspects of
UF-foam insulation, rate UF foam as a combustible material. The codes
require that, when used on the inside of buildings, the UF foam must
be protected by a thermal barrier of fire-resistant material. In
England and Holland, UF insulation materials are certified for use
only in masonry cavities of buildings.

If the foam insulation is improperly mixed, or if improperly
formulated UF resin is used, 159 16 the insulation may release
formaldehyde into the building. Specific factors that have been
identified as contributors to formaldehyde release include excessive
formaldehyde in the resin concentrate, excessive acid catalyst in the
foaming agent (especially important) , excessive foaming agent
(surfactant), foaming during periods of high humidity and temperature,
foaming with cold chemicals (optimal temperature, 50-80F) , improper
use of vapor barriers, improper use of foams (in ceilings, etc.), and
excessive resin. 2 116

Combustion Appliances

Several recent studies have reported on combustion-generated
indoor air pollutants, namely air contaminants from gas stoves and
heating systems in residential buildings. Laboratory studies have
shown that gas stoves emit substantial aldehyde; formaldehyde has been
identified as the major component of the aldehydes measured (Schmidt
and Gotz; 15 * G. Traynor, personal communication). Formaldehyde
emission rates for a gas stove have been measured at approximately

83

25,000 yg/h and 15,000 yg/h for the oven and each top burner,
respectively (Traynor, personal communication).

Tobacco Smoke

Tooacco smoke is a source of several chemical pollutants,
including aldehydes (Table 5-19), that can reach high concentrations
in the indoor environment. The smoker's exposure to the chemical
pollutants results principally from smoke inhaled directly into the
lungs (mainstream smoke) . The smoke that is not inhaled directly into
the lungs enters the space surrounding the smoker (sidestream smoke) .
It is the sidestream smoke that is the major contributor to indoor
pollution. The inhalation of tobacco smoke involuntarily, commonly
referred to as "passive smoking," has only recently been the subject
of investigation. Analysis by Hobbs e_t al_. 1<46 indicated acrolein to
be an important component of tobacco smoke. Weber 95 used a smoking
machine in an environmental chamber and identified substantial amounts
of acrolein. Data on formaldehyde, acetaldehyde, and acrolein in
cigarette smoke are presented in Table 5-20.

Harke et al^ a measured concentrations of nicotine, carbon
monoxide, acrolein, and aldehydes (expressed as acetaldehyde) in the
air of an unventilated room in which a series of experiments with a
smoking machine were performed. Important concentrations of all four
of these compounds were observed in these experiments; however, the
number of cigarettes per unit time was unusually high.

It has been demonstrated that the quality of smoke from Hurley
tobacco depends on the potassium and magnesium composition of the
leaves. 11X When potassium was applied to the soil at 224
kg/hectare, the aldehyde content of tobacco smoke increased from 0.41
to 0.55 mg/cigarette. At the same time, the total particulate
material in cigarette smoke decreased. Thus, the researchers were
faced with both harmful and beneficial effects on smoke quality and
therefore recommended bioassays to evaluate the potential consequence
for health.

AGRICULTURAL AND DISINFECTANT PRODUCTS

Commercially grown plants require fertilizers for optimal growth
and pesticides for disease control. Both may involve the use of
aldehydes and theoretically could contribute to the aldehyde content
of indoor air . Urea-formaldehyde polymers represent one of several
groups of fertilizers and are used not only to obtain a more uniform
release rate than is possible with soluble nitrogen, but also to
minimize the hazards of water pollution by nitrates leached out of the
soil. 76 Fertilizers with aldehyde compounds as a source of
slow-release nitrogen have been used on field crops, 76
turfgrass, 1B 6 pine seedlings, 19 and geranium. 176

Formaldehyde has been used in a wide variety of agricultural
operations to disinfect seeds, bulbs, roots, soil, and contaminated

84

TABLE 5-19
Aldehydes Identified in Tobacco Smoke 3

Aromatic Aromatic

Formaldehyde Benzaldehyde

Acetaldehyde

Glyoxylic Acid

Propanal Cyclic

2-Oxopropanal

n-Butanal Furfural

Jsobutanal 5-Hydroxymethylf urf ural

Galactose

Olefinic

Acrolein
Crotonaldehyde

a Data from Graedel.

TABLE 5-20
Quantities of Some Aldehydes in Cigarette Smoke

Amount in
Cigarette Smoke,

Aldehyde

mg/cigarette

Reference

Acetaldehyde

0.18-1.44

181

Acrolein

0.7

95

Formaldehyde

0.02-0.04

181

85

equipment, such as pots, tools, storage bins, and greenhouses.
Walker 187 described its use to disinfect wheat and barley by
steeping in a formaldehyde solution (1 pint of formalin in 40 gal of
water) for 5 min and then holding in a covered container for 2 h.
Leafspot in beets is prevented by dipping in a solution of 1 pint of
formalin in 8 gal of water. Bacterial blight in celery is combatted
by soaking seeds for 15-30 mm in a solution of 1 pint of formalin i
32 gal of water. Williams and Siegel 191 * found bactericidal
concentrations of formaldehyde on the shells of eggs exposed to
formalin at 1.2 ml/ft 3 of incubator space. Infected laboratory
animal housing can be decontaminated with paraformaldehyde at 10
g/m 3 heated to 232C to release formaldehyde. 136

Glutaraldehyde in 2% alkaline solution has a germicidal spectrum
similar to that of formaldehyde, although it is more expensive and
less stable. 16 3

There are at least 60 registered pesticides containing
formaldehyde and 75 containing paraformaldehyde as active
ingredients. At prescribed rates, they can be used on some vegetabl
field, and ornamental crops. Formaldehyde can also be used on
equipment used in the culture of mushrooms, potatoes, and other crop

Formaldehyde is an effective disinfectant against bacteria, fung
and viruses. It kills bacteria in 6-12 h in concentrations of 1:200
and bacterial spores in 2-4 d. It is effective against tubercle
bacilli. It is used in dilute solutions as a disinfectant and
preservative in cosmetics (see Chapter 7) . Formaldehyde is used in
variety of applications as a preservative and tissue fixative for
biologic and histologic specimens and in embalming. 163

OTHER CONSUMER PRODUCTS

Urea-formaldehyde resin is used by the paper industry to give
increased wet strength to various gtades of paper. Typical paper
products treated with UF resin include grocery bags, waxed paper,
facial tissues, napkins, paper towels, and disposable sanitary
products. Formaldehyde polymers are used extensively in the
manufacture of floor coverings and as carpet backing. UF resin is
used in binders in the textile industry to improve the adherence of
pigments, fire retardants, or other material to cloth. It is also
used to impart stiffness, wrinkle resistance, and water repellency 1
fabrics.

THE MECHANISM OF ALDEHYDE GENERATION IN THE ATMOSPHERE
THE UNPOLLUTED, NATURAL ATMOSPHERE

There are natural precursors of formaldehyde even in the
atmosphere that is unpolluted by man. It contains methane, CH4, at
about 1.6 ppm and smaller amounts of various other hydrocarbons tha
are emitted from the earth through natural processes escape of gas<

86

from the earth, tree and plant emission, etc. The reaction of these
naturally occurring hydrocarbons with photochemically generated HO
radicals is the major natural source of formaldehyde in the clean
lower troposphere. The HO-radical is formed through a variety of
reactions. One important reaction sequence is initiated by the
photodissociation of ozone, 3 , at the short wavelengths present in
sunlight:

3 + hv(X < 3200 A) + O^D) + 2 ( 1 Z g + , 1 A g , or 3 Z g ") (1)

The O(^-D) atom is an electronically excited species that may be
deactivated to a normal ground-state atom, 0( P), by collisions with
02 and N 2 in the air (Reaction 2), or it may, on encountering a
water molecule, form HO radicals (Reaction 3):

0(1-0) + N 2 (or 2 ) f 0( 3 P) + N 2 (or 2 ) (2)

O^D) + H 2 + 2HO (3)

The HO radicals react in part with hydrocarbons present in the
atmosphere. In the case of reaction with methane, the following
reaction sequence (somewhat abbreviated) may occur and lead to
formaldehyde :

HO + CH 4 + H 2 + CH 3 (4)

CH 3 + 2 (+ N 2 or 2 ) + CH 3 2 (+ N 2 or 2 ) (5)

CH 3 2 + NO * CH 3 + N0 2 (6)

CH 3 2 + CH 3 2 * CH 3 + CH 3 + 2 (7)

- CH 3 OH + HCHO + 2 (8)

CH 3 + 2 * HCHO + H0 2 (9)

Formaldehyde absorbs the short wavelengths of sunlight
(X < 3700 A) and undergoes photodecomposition. It is also
destroyed by reactions with the HO radical and other reactive
atmospheric species. Levy used a somewhat incomplete reaction
mechanism involving these various formaldehyde formation and decay
processes with the rate-constant estimates then available to estimate
the theoretical formaldehyde concentration-versus-altitude profile
shown in Figure 5-1. A more complete reaction scheme and updated rate
and photochemical data lead to somewhat higher formaldehyde
concentrations than those predicted by Levy. 37

Thus, one anticipates in theory that, in the clean atmosphere near
ground level during the daylight hours, the formaldehyde concentration
will be around 1.4 x 10 10 molecules/cm 3 (about 0.0006 ppm) , owing
to the chemistry involving only the naturally occurring components of

87

the atmosphere. Indeed, concentrations of this magnitude are observed
even in the remote and seemingly uncontaminated regions of the lower
atmosphere. If one were to include formaldehyde source terms from the
naturally occurring nonmethane hydrocarbons, a somewhat higher
ground-level formaldehyde concentration is anticipated.

The Mechanism of Aldehyde Generation within the Polluted Lower
Atmosphere

In addition to the clean-air mechanism of formaldehyde generation
outlined briefly in the preceding section, many other reactions occur
within the polluted troposphere that lead to the formation of
formaldehyde and the higher aldehydes. The major sources are the
reactions of the anthropogenic and natural nonmethane hydrocarbons
(alkanes, alkenes, and aromatic hydrocarbons) with HO radicals and
ozone present in the atmosphere. It will be instructive to consider
here some examples of these important reaction mechanisms.

The Aldehyde-Generating Reactions of the HO Radical with the Alkanes

There is now an abundance of both di-rect experimental and
theoretical evidence that the reactive HO radical is present in the
sunlight-irradiated lower atmosphere; for examples, see Calvert, 35
Wang et_al_., 188 Davis et_al_-/ 52 53 Calvert and McQuigg, 39 and
Crutzen and Fishman. 1 * 9 These HO radicals formed within the
atmosphere react by H-atom abstraction with all the impurity-alkane
molecules present in the air. The rate constants for these reactions
are very much larger for the higher-molecular-weight hydrocarbons than
for methane, and all the reactions lead to aldehyde formation at least
in part. As an example, consider the reactions initiated by the
attack of HO on n_-butane, n_-C4Hio, a typical alkane impurity found
in the urban atmosphere. Both secondary and primary H atoms may be
abstracted in this case:

CH 3 CH 2 CH 2 CH 3 + HO - CH 3 CH 2 CH 2 CH 2 + H 2 (10)

- CH 3 CHCH 2 CH 3 + H 2 O (11)

The rate of Reaction 11 is about 3.5 times that of Reaction 10 at
25C. Even the slower of these two reactions has a rate constant
about 200 times larger than that of HO radical with methane (Reaction
4). To illustrate the mechanism in which the aldehydes are formed
following Reactions 10 and 11, the sequence of reactions of the
n_-butyl radical, 4%, product of Reaction 10 may be considered in
Figure 5-7; the aldehyde products are highlighted by enclosing them in
boxes. Note that, during the course of these reactions, every
possible straight-chain aldehyde of four or fewer carbon atoms is
formed. Some other reactions of the alkylperoxy, RO2r and alkoxy,
RO, radicals not shown in Figure 5-7 compete with those given here,

88

(0,)

(NO)

CH 3 CH 2 CH 2 CH 2 *- CH 3 CH 2 CH 2 CH 2 2 - - CH 3 CH 2 CH 2 CH 2 0- +N0 2

JCH 3 CH 2 CH 2 CHO

3 CH 2 CH 2 C00 2
| (NO)

CH 3 CH 2 CH 2 C0 2 +N0 2
CH 3 CH 2 CH 2 -+C0 2

CH 3 CH 2 CHO

+ H0 2

(0 2 )
CH 2 CH 2 2 -

| (NO)
CH 3 CH 2 CH 2 0- +N0 2

X

X

I 3 CH 2 C00 2 -
,(NO)

CH 3 CH 2 -+HCO

CH 3 CH 2 C0 2 +N0 2
CH 3 C TT '

,(NO)
CH 3 CH 2 0-+N0 2

CH 3 CHO

X

CH 3 CH 2

HCHO

HCHO

HCHO

FIGURE 5-7 Example of aldehyde-forming reaction sequences after
n-butyl radical generation from n-butane in polluted troposphere;
pathways shown by dashed arrows are much less Important than those
shown by solid arrows.

89

but the aldehyde-forming reactions are expected to dominate in the
polluted atmosphere.

A similar set of reactions occurs following Reaction 11 in which
HCHO, CH3CHO, CH3CH2CHO, and methyl ethyl ketone are the
expected major products. Indeed, all the impurity-alkane molecules
present in the polluted atmosphere are potential sources of the
aldehydes through similar reaction sequences. For further examples
and a consideration of the detailed reaction mechanisms of hydrocarbon
photooxidation, see Demerjian ^t al. 55 Present evidence suggests
that the major atmospheric loss mechanism for the alkanes involves HO
attack on these species. If one assumes an HO-radical concentration
for the polluted troposphere that is consistent with theory and
experiment, about 3 x 10~ 7 ppm, then the half-life of ri-butane may
be estimated from the sum of the known rate constants, k]_o + kiif
to be about 10 h. 10 Other representative alkanes, such as isobutane
and isopentane, have similar half-lives about 10 and 8 h,
respectively. During this rather short period in which the typical
alkane decays, the photooxidation reactions commonly lead to more
aldehyde molecules than molecules of hydrocarbon that have reacted.

The Aldehyde-Generating Reactions of the HO Radical with Alkenes

The most reactive class of hydrocarbons, the alkenes, also are
major sources of aldehydes. The HO radical is only one of the
reactants that stimulate aldehyde formation in this case. The
mechanism of the reactions can be illustrated with the simple alkene,
propylene, 3^. The complete mechanism of the HO-alkene
reactions is not entirely clear, but it now appears probable that the
dominant primary reaction is HO addition to the carbon-carbon double
bond of the alkene; presumably, both terminal and internal additions
may occur with propylene:

CH 3 CH = CH 2 + HO -> CH 3 CHCH 2 OH ( 12 )

OH
-*CH 3 CHCHj

90

The radical product of Reaction 12 may react by the following possible
steps:

00-
- CH 3 CHCH 2 OH + O 2 ->CH 3 CHCH 2 OH

6

CH 3 CHCH 2 QH + NO 2
J(0 2 )

II
H0 2 + CH 3 CCH 2 OH

CH 2 OH

+ HO,

In a similar fashion f the radical product of Reaction 13 may form
formaldehyde and acetaldehyde, among other products. The rate
constants for the HO-radical reaction with the alkenes are in general
larger than those for the alkanes. 10 For the typical HO-radical
concentration in the sunlight-irradiated, polluted troposphere,
[HO] a 3 x 10~ 7 ppm, and propylene, isobutene, and trans-2-butene
have half -lives of only 1.0, 0.5, and 0.4 h, respectively. Because
the aldehydes are major products of this rapid interaction, the
HO-alkene reactions are expected to be major sources of aldehydes in
the usual hydrocarbon-polluted atmosphere.

Aldehyde Generation through the Ozone-Alkene Reactions

As ozone builds up in a sunlight-irradiated, polluted atmosphere,
the interaction of ozone with the impurity-alkene molecules can become
important, and reactions between these molecules are an efficient
source of aldehydes. In illustration, consider the attack of ozone on
propylene. The primary reaction leads to an unstable, energy-rich
ozonide (Reaction 14) . Both theory and experiment suggest that, in
the atmosphere, this species will react rapidly, in part to form
aldehydes (Reactions 15 and 16) :

3 + CH 3 CH = CH 2 -> CH 3

CH 3 CHO

0-0-0
CH CH

CH 2 00

HCHO

+ CH 3 CHOO other products

(14)

91

The intermediate CH 2 2 and CH 3 CH02 species formed in Reactions
15 and 16 may fragment by a variety of reaction paths, but they may
also lead to aldehydes through Reactions 18-21 when easily oxidized
compounds, such as NO and SC>2, are present: 1 * 1

CH 2 2 +NO

CH 2 O 2 +SO 2

CH 3 CH0 2 +NO

CH 3 CHO 2 +SO 2

HCHO

+ N0 2

HCHO

+ S0 3

CH 3 CHO

+ N0 2

CH 3 CHO

+ S0 3

(18)
(19)
(20)
(21)

Present evidence 117 12I * u suggests that a significant fraction
(greater than 20%) of the gas-phase ozonolysis of the simple alkenes
proceeds through the so-called Criegee mechanism, of which Reactions
15 and 16 are critical parts. Again, aldehydes are among the major
products formed.

The half -lives of the impurities of propylene, isobutene, and
trans-2-butene for reaction with ozone in a highly polluted
atmosphere, where the concentration of ozone may be about 0.2 ppm, are
3.7, 3.3, and 0.2 h, respectively. 63 90 Because aldehydes are major
products of this system, it is evident that the ozone-alkene reactions
may be an important source of aldehydes in the polluted atmosphere.

In most urban areas, the total amount of aldehydes from direct
emission (autos, refuse burning, chemical plants, power plants, etc.)
is usually below that of the nonmethane reactive hydrocarbons. As we
have seen, the atmospheric chemistry results in the formation of at
least one molecule of aldehyde from each molecule of hydrocarbon
within a relatively short period (a few hours to a few days). Thus,
it appears that the largest share of the total aldehyde content of
urban air is created in the atmosphere from hydrocarbon precursors and
that control of the direct emission of hydrocarbon, as well as
aldehydes, will be a necessary part of any newly developed strategy to
control ambient concentrations of the aldehydes.

ALDEHYDE REMOVAL PROCESSES OPERATIVE IN THE ENVIRONMENT

The accumulation of aldehydes in the atmosphere is suppressed by
several natural removal processes. Many of the chemical steps are
seemingly well understood; other chemical and physical processes
remain speculative. The action of sunlight on the aldehydes results
in their decomposition. The reaction of the reactive molecular
fragments that are present in the atmosphere HO, HO2/ 0( 3 P), and
N0 3 may also result in chemical degradation or transformation of
the aldehydes. These and other important natural removal processes
are considered in this section.

92

THE PHOTODECOMPOSITION OF THE ALDEHYDES

There is a substantial overlap between the ultraviolet-wavelength
region of the light absorbed by the simple aldehydes and the solar
spectral distribution incident on the earth's surface. This can be
seen in Figure 5-8 for formaldehyde, acetaldehyde, and
propionaldehyde. The rather weak absorption bands in the
near-ultraviolet region for the aldehydes originate from a weakly
allowed n - IT* electronic transition, which involves largely the
promotion of an electron in a nonbonding (n) orbital on oxygen to the
antibonding TT* orbital associated with the carbon-oxygen double bond
in the aldehyde.

The initial electronically excited states of the aldehydes that
are formed in this process are short-lived, and a large fraction of
the excited molecules undergo molecular fragmentation or rearrangement
very quickly. In the case of formaldehyde, the decay of the excited
molecules occurs efficiently through either of two primary processes:

HCHO + hv - HCHO* - H + HCO (I)

+ H 2 + CO (II)

Many measurements of the quantum efficiencies of these
processes i.e., the fraction of the excited molecules that decay by a
given path have been made in recent years; for a review of this
extensive literature, see Calvert. 37 The results derived from two
of these studies that should be most applicable to the reactions in
the lower atmosphere at 25C are summarized in Figures 5-9 and 5-10.
It is apparent from these data that the quantum yield of fragmentation
of excited formaldehyde into the reactive free-radical fragments, H
and HCO, in process I (<|>j) increases from near zero at 3380 A to
near 0.8 at 3000 A. Process II, forming molecular hydrogen and carbon
monoxide, has a longer wavelength onset, and <j>n maximizes near
3350 A.

After process I in air at 1 atm, the radicals formed react largely
through Reactions 22 and 23 to generate H02 radicals and carbon
monoxide:

H + 2 (+ N 2 or 2 ) + H0 2 (+ N 2 or 2 ) (22)

HCO + 02 * H0 2 + CO (23)

The photolysis of formaldehyde in air can be a major source of the
HO 2 radical.

If one couples the formaldehyde-absorption data, 16 the primary
quantum-yield estimates for processes I and II (Figures 5-9 and 5-10) ,
and the actinic-flux data for various solar zenith angles, 56 the
apparent first-order rate constants Jj and Jjj for the occurrence
of processes I and II, respectively, in air can be calculated. These
and the total decay constant for formaldehyde photodecomposition (Jj
+ J) are shown in Figure 5-11; here, the rate of process I (or II)

93

I ' I ' I ' I ' I

2000 2200 2400 2600 2800 3000 3200 3400 3600 3800

Wavelength, A

FIGURE 5-8 Absorption spectra for (1) formaldehyde, 75C;
(2) acetaldehyde, 25C; (3) propionaldehyde, 25C (reprinted
with permission from Calvert and Pitts ). Curve 4, actinic
flux received at ground level for typical atmospheric condi-
tions during the day (reprinted with permission from Demerjian
et al. 55 ). e = log (I /I) /[aldehyde]^, L/mol-cm.

94

1 -

CH 2 +hv

HCO(I)

02-

o '

2700

\0
i t l

3000 3300 3600

WAVELENGTH. A

FIGURE 5-9 Wavelength dependence of primary quantum yield of process I
in formaldehyde photolysis. Closed circles, data of Horowitz and

Pa 1 -WOT-!- - J "" flnon r-irflaa Hnf-a r\f Mnnvt-ofl t- artf\ Wa vnaflt -

Calvert.

Open circles, data of Moortgat and Warneck.

95

CH 2 +hv

(E)

08-

6-

04-

I I I I
3000 3300

WAVELENGTH, A

3600

FIGURE 5-10 Wavelength dependence of primary quantum yield of
process II in formaldehyde photolysis. Closed circles, data of
U,-T.T< t-~ * n A r Q iw Q T-t- o'>o Open circles, data of Moortgat and

96

I

20

till
40 60

SOLAR ZENITH ANGLE

80

FIGURE 5-11 Theoretical first-order decay constants for photo-
decomposition of formaldehyde by primary processes I and II in
lower troposphere as function of solar zenith angle; J-j-, solid

circles] Jjp triangles; Jj +
from Calvert.

open circles. Reprinted

97

is given by R T (or R TI ) = J T (or J ZI ) [HCHO] . With a solar
zenith angle (angle between the sun and the vertical line
perpendicular to the earth's surface at the point of observation) of
0, 20, or 40, the half-life of formaldehyde decay by photo-
decomposition in the atmosphere near sea level is expected to be 3.2,
3.4, or 4.2 h, respectively. The rates of H0 2 -radical generation
through the occurrence of process I (R H09 = 2J.j.[HCHO]) can be
reasonably large and may influence the timing of the chemistry that
controls ozone formation.

The nature of the photochemical decay paths and their quantum
efficiencies in air are less well established for the higher aliphatic
aldehydes, acrolein, and the aromatic aldehydes. However, present
evidence shows that both free-radical and intramolecular primary
processes occur; the chemical nature of these processes for the first
few members of the aliphatic aldehyde series are as follows: 1 *

CH 3 CHO + hy -> (CH 3 CHO)* -> CH 3 + HCO (III)

^

(0 2 )\ CH 4 + CO (IV)

\
products 9

+ hy->(CH 3 CH 2 CHO)* ->C 2 H 5 +HCO (V)

(VI)
products?

CH 3 CH 2 CH 2 CHO + to -* (CH 3 CH 2 CH 2 CHO)*^ n - C 3 H 7 + HCO (VII)

"C 3 H 8 +CO (DO

(0 2 )\ C 2 KU + CH 2 = CHOH 00

T

CH 3 GHO
products 9

Although many studies related to these processes have been made, the
quantum efficiency of each for molecules in air at 1 atm remains
unclear. Thus, Demer^ian t al. 5S have reviewed the present
information on acetaldehyde primary quantum yields, and they could
suggest only a large range of values that may apply for processes III
and IV. From the data of Table 5-21, it can be seen that the

98
TABLE 5-21

Estimated First-Order Rate Constants for Photodecoraposition of
Acetaldehyde as Function of Solar Zenith Angle (x ) in Lower Atmosphere a

Rate Constant, s

-1

x

deg.

Process III
Upper Limit

Lower Limit

Process IV
Upper Limit

Lower Limit

3.

75 x

io- 5

7.22

x

IO- 6

1.

48

x 10" 6

3.42

x 10~ 7

10

3.

69 x

io- 5

7.10

X

ID" 6

1.

45

x 10" 6

3.34

x 10

20

3.

51 x

io- 5

6.65

X

10" 6

1.

32

x 10" 6

3.04

x 10" 7

30

3.

19 x

io- 5

5.90

X

10~ 6

1.

13

x 10" 6

2.58

x 10

40

2.

75 x

io- 5

4.88

X

10" 6

0.

87

x 10" 6

1.98

x 10~ 7

50

2.

17 x

io- 5

3.64

X

10" 6

0.

59

x 10" 6

1.32

x 10~ 7

60

1.

48 x

io- 5

2.28

X

10" 6

0.

31

x 10" 6

0.70

x IO" 7

70

0.

76 x

io- 5

1.02

X

10" 6

0.

11

x 10~ 6

0.24

x 10" 7

78

0.

29 x

ID" 5

0.33

X

10~ 6

0.

03

x 10" 6

0.06

x 10" 7

8b

0.

05 x

io- 5

0.05

X

10" 6

0.0

03

x IO- 6

0.006

x 10" 7

Reprinted with permission from Demerjian et al. 56

99

theoretical half-life of acetaldehyde from photodecomposition in the
lower atmosphere (x = 0) is 4.9-25 h.

Estimates of the range of photodecomposition rate constants for
propionaldehyde and butyraldehyde decay in the lower atmosphere ( x =
40) have been made by Demerjian et_ al_. 5 5 with the older estimates
of actinic irradiance given by Leighton; 112 these are summarized in
Table 5-22. Theoretical photodecomposition half-lives of these
aldehydes in air (x = 40) are in the range of those estimated for
the other simple aldehydes (4-9 h) .

All the photodecomposition data on the simple aldehydes suggest
that the photodecomposition reactions are major loss reactions and
that these decay paths can be an important source of free radicals in
the atmosphere. The occurrence of processes III, V, and VII in the
lower atmosphere will always be followed by the formation of an
alkylperoxy radical (CH 3 O 2 f C2H 5 O 2 , or -0311702) and a
hydroperoxy radical (HO 2 ) :

CH 3 + O 2 > CH 3 2 (5)

C 2 H 5 + 2 + C 2 H 5 2 (24

n-C 3 H 7 + O 2 - n-C 3 H 7 2 (25

HCO + O2 * HO2 + CO (23

These radicals act to initiate the chain oxidation of NO to N0 2 and
in turn can influence the concentration of ozone reached in the
polluted atmosphere.

REACTIONS OF THE ALDEHYDES WITH REACTIVE INTERMEDIATES IN THE
ATMOSPHERE

Several of the reactive species that are present in a
sunlight-irradiated, NO X - and hydrocarbon-polluted atmosphere react
measurably with the aldehydes. These include HO, 0(^P), HO 2 ,
N0 3 , and 3 . Bimolecular rate constants for these reactions with
some of the aldehydes have been determined and are summarized in Table
5-23. Typical concentrations of the reactive intermediates in highly
polluted air, as estimated theoretically by computer simulation (J.G.
Calvert and W.R. Stockwell, personal communication) , and the
approximate relative rates of attack of these species on formaldehyde
are summarized in Table 5-24.

The transient species whose rates of reaction with formaldehyde
appear to be of particular importance are those for the HO and H0 2
radicals. The reaction with NO 3 may contribute a small amount, and
it may be the dominant loss reaction for nighttime conditions for
which the N0 3 concentration may remain high as the N0 2 -O 3
reaction continues to generate this species. In the case of the HO

and N05 radicals, the reactions are those of H-atom abstraction from

100

TABLE 5-22

Theoretical Estimates of First-Order Decay Constants for Propionaldehyde
and n-Butyraldehyde in Lower Atmosphere (X = 40) a

Process Rate Constant, s

C 2 H 5 CHO + hv >C 2 H 5 + HCO ( V) (4.2-2.0) x 10" 5

>C 2 H 6 + CO (VI) 1.0 x 10~ 6

n-C 3 H 7 CHO + hv > JT C 3 H 7 + HCO (VII) (3.2-2.2) x 10" 5

> C 3 H 8 + CO (IX) 1.0 x 10" 6

> C 2 H 4 + CH 3 CHO (X) 1.0 x 10~ 5

a Reprinted with permission from Demerjian et al.

101
TABLE 5-23

Bimolecular Rate Constants for Reactions of Various Reactive
Atmospheric Species with Aldehydes

Reactive Rate Constant at 25C,

Species Aldehyde cc-molec s Reference

HO HCHO (1.4 + 0.35) x 10" 11 130

(1.5 + 0.1) x 10' 11 142

(0.65 + 0.15) x 10' 11 165
(0.94 + 0.10) x lO" 1 ! 11

(0.99 + 0.11) x 10' 11 169

CH 3 CHO (1.5 + 0.38) x 10~ n 132

(1.60 + 0.16) x 10" 11 11

(1.6 + 0.2) x 10" 11 142
>2.0 x 10~11 48

C 2 H 5 CHO (2.1 + 0.1) x 10~U 142

C 6 H 6 CHO (1.3 + 0.1) x 10" 11 142

0( 3 P) HCHO (1.5 + 0.5) x 10"]- 3 84

(1.5 +0.2) x ICT^ 121

1.64 x 10~ 13 138

(1.50 + 0.10) x 10"" 106

(1.61 + 0.17) x 1Q~ 1J 105

(1.9 + 0.4) x 10~ 13 44

CHoCHO 4.3 x IQ'^ 162

J 4.8 x 10~ 13 122

4.5 x 10~ 13 31

5.0 x 10' 13 50

C 9 H,-CHO 7.0 x I0~;j- 3 162

25 2.3 x 10' 13 30

n-CoH 7 CHO 9.5 x 10" ?- 3 162

- 3 7 2.5 x ID' 13 92

iso-C 3 H 7 CHO 1.2 x 10~ 12 162

CH 9 =CHCHO 2.7 x 10~?- 3 30

Z 4.9 x 10" 1J 65

CUoCH-CHCHO 0.83 x 10'^ 30

J 1.09 x 10~ 1Z 65

N0 3 CH 3 CHO 1.2 x 10" 15 131

H0 2 HCHO l.OxlO' 14 172

3 HCHO <2.1 x 10" 24 24

102

TABLE 5-24

Typical Theoretical Concentrations of Reactive Intermediates
in Sunlight- Irradiated, NO - and RH-Polluted Atmosphere, Approximate
Rate Constants, and Relative Rate of Attack of These Species
on Formaldehyde (25C, 1 atm)

Approximate
Typical Concentrations Rate Constant, Relative Rate

Species

molec/cc

ppm

cc

.mo lee" s

Reaction w:

HO

7

.4 x

10 6

3 x

10

-7

1.

1 x

ID" 11

1

.00

HO 2

4

.9 x

10 9

2 x

10

-4

1.

x

ID' 14

.61 a

N0 3

2

.5 x

10 9

1 x

10

-4

1.

2 x

10 -15b

.036

0( 3 P)

1

.7 x

10 5

7 x

10

-9

1.

6 x

W 13

.00034

3

4

.9 x

10 12

2 x

10

-1

<2.

1 x

W 2 *

1

.3 x 10~ 7

a Rate of addition; net rate is lower as result of reverse reaction.
b Taken as equal to that for NO^ + CH 3 CHO measured by Morris and Niki. 131

103

formaldehyde; the CHO radical formed here will react primarily to form
HC>2 and carbon monoxide:

HO + HCHO + H 2 + HCO (26)

N0 3 + HCHO -> HONO 2 + HCO (27)

HCO + 2 + H0 2 + CO (23)

For the HC^-radical reaction, recent studies show that the addition
of the radical to formaldehyde, rather than H-atom abstraction, is the
major step: l 7 l 172

H0 2 + HCHO - (H0 2 CH 2 0) - O 2 CH 2 OH (28)

However, the reverse of this reaction does occur with k 2 g * 1.5
s"" 1 (25C) , and the removal of formaldehyde does not result witn
each occurrence of Reaction 28:

O 2 CH 2 OH - (H0 2 CH 2 O) + H0 2 + HCHO (29)

In laboratory studies, the O 2 CH 2 OH radical has been shown to
react either by dissociation (Reaction 29), by disproportionation with
H02 radicals (Reaction 30), or by disproportionation with other
O 2 CH 2 OH radicals (Reaction 31) :

H0 2 + O 2 CH 2 OH + H0 2 CH 2 OH + O 2 (30)

2O 2 CH 2 OH + 20CH 2 OH + 2 (31)

The unusual, newly identified compound, H02CH 2 OH, forms formic
acid in laboratory experiments through the overall reaction:

HO 2 CH 2 OH + HCO 2 H + H 2 (32)

The OCH 2 OH radical product of Reaction 31 reacts rapidly to form
HC0 2 H:

OCH 2 OH + 2 HCO 2 H + H0 2 (33;

It has been estimated that the rate of HO^jCH^H generation in a
typical, highly polluted atmosphere in which [HCHO] s 0.02 ppm and
[HO 2 ] ~ 2 x 10 ppm will be about 0.4 ppt/min. Conceivably,
these or related reactions account for a portion of the HCO 2 H that
is generated in highly polluted atmospheres.

It is instructive to compare the relative rates of removal of
formaldehyde by the various chemical and photochemical pathways that
have been described. In making the estimates in Table 5-25, the
theoretical concentrations of the reactive species shown in Table 5-24
were used. It is seen that the attack on formaldehyde by the HO
radical and the photodecomposition of formaldehyde are the two

104

TABLE 5-25

Theoretical Relative Rates of Major Chemical and Photochemical
HCHO Removal Reactions for Highly Polluted, Sunlight-Irradiated
(X = 0) Lower Atmosphere

Relative Rate
Reaction (approximate)

HCHO + hv >H + HCO (I)

0.57
>H 2 + CO (II)

HCHO + HO ^HCO + H 2 (26)

HCHO + H0 2 ^^0 2 CH 2 OH (28,29)1

l" >0.0082

H0 2 + 2 CH 2 OH >H0 2 CH 2 OH + 2 (30) J

N0 3 + HCHO ^HON0 2 + HCO (27) 0.037

105

dominant homogeneous pathways for formaldehyde removal in the polluted
atmosphere. The relative rate of removal as a result of the
reversible H0 2 -radical addition reaction and the later reaction of
the O 2 CH 2 OH radical is shown as a lower limit, because other
radical reactions of this species (possible with CH 3 2 , R0 2 ,
etc.) will probably act as a permanent sink as well and also compete
with the dissociation reaction (Reaction 29).

If the processes considered here alone describe the removal of
formaldehyde in the lower atmosphere, then the half-life of
formaldehyde for these conditions, typical of the highly polluted
atmosphere, would be somewhat less than 2.6 h. Ill-defined
heterogeneous reaction pathways involving rainout of formaldehyde and
removal by surface water, rock, and soil must also occur and shorten
the lifetime of formaldehyde. Thus, O.C. Zafiriou and A.M. Thompson
(personal communication, 1979) estimated that in the vicinity of Woods
Hole, Massachusetts, formaldehyde enters the ocean from the atmosphere
at the rate of 6 yg/cm 2 per year. The flux of gaseous
formaldehyde into the sea at a remote, marine site in the equatorial
Pacific was measured by Zafiriou et^ al^. 1 9 7 at 5 yg/cm 2 per year;
for these same conditions, the rainout and washout of formaldehyde
amounted to about 1 pg/cm 2 per year. These various processes
restrict the formaldehyde buildup in the atmosphere.

The atmospheric transport of the aldehydes over long distances is
probably not very important, because of their short lifetimes. It is
probably less important as a source of aldehydes in remote areas than
the local generation from transported, longer-lived precursors, such
as the less reactive hydrocarbons. The lifetime of formaldehyde in
aqueous media may be somewhat greater, because the hydrated form of
formaldehyde (HOCH20H) dominates in these conditions, and it does
not absorb sunlight appreciably. In this case, microorganisms in the
water appear to play an important role in the degradation process,
which may take 30-72 h under natural conditions commonly encountered.

All available evidence at hand suggests that the removal paths for
acetaldehyde, propionaldehyde, etc., are very similar to those
outlined for formaldehyde. The accuracy of the data on these
compounds does not warrant a detailed analysis now.

The commonly observed unsaturated aldehyde, acrolein, is
comparatively stable toward photodecomposition. ll|S In view of this,
it has been suggested that there may be a higher persistence for
acrolein than the other aldehydes in photochemical smog a conclusion
of special interest, in light of the high degree of eye irritation
attributed to acrolein. The HO attack on acrolein is expected in
theory to be the dominant removal mechanism, although estimates of the
rate constant for this reaction have been made only by theoretical
methods. Acrolein and crotonaldehyde appear to be as reactive as the
aliphatic aldehydes in photooxidation in NO x -con tain ing mixtures,
and it is likely that their lifetimes in the atmosphere are determined
largely by the rate of HO-radical attack. 1 * 57

The photochemistry of benzaldehyde and the higher homologues of
the aromatic aldehydes is marked by the relatively high photochemical
stability of the excited states toward decomposition. In

106

solution-phase studies, photoreduction and electronic energy-transfer
processes are commonly observed with these compounds. 1 *
Benzaldehyde , 2-methylbenzaldehyde, and 3-methylbenzaldehyde show very
low reactivity when photooxidized in dilute N0-N0 2 mixtures in air
in smog-chamber experiments. 57 In contrast, 1-methylbenzaldehyde
shows a high reactivity characteristic of the aliphatic aldehydes.
Present data do not allow quantitative estimates of the half-lives of
the aromatic aldehydes toward photodecomposition or other possible
light-induced reactions, but they appear to be somewhat longer than
those observed for the aliphatic aldehydes in most cases.

REMOVAL PROCESSES IN AQUEOUS SYSTEMS

Very little information is available on the factors that affect
the stability of aldehydes in aqueous systems. This section addresses
reactions that could occur in the aquatic environment with the
carbonyl group. It should be noted that some aldehydes may have other
functional groups that contribute to or dominate their chemistry in
aqueous systems.

A reaction that many aldehydes undergo in water is hydration at
the carbonyl group (s) to produce gem-diols (gem = geminal, with both
hydroxyl groups on the same carbon atom) :

RCHO + H 2 - RCH(OH) 2

The extent of hydration depends on the nature of the R group (or
substituent) ; electron-withdrawing substituents favor a greater degree
of hydration. 17 The degrees of hydration at equilibrium, calculated
from the hydration-rate data of Bell and McDougall J 8 and Smith 16 "
for formaldehyde, chloral, acrolein, and acetaldehyde are 99.9, 99.8,
95.0, and 60.0%, respectively, at 25C.

At a given temperature, the ratio of the nonhydrated to the
hydrated form of an aldehyde in water is constant. Determining
chemical and biologic transformation and transport processes of
aldehydes can be difficult, because the hydration equilibrium will
shift to replenish the form removed by these processes. Because the
hydration reaction is associated with a complex kinetic expression
that entails both kinetic and equilibrium processes, it is difficult
to estimate the simple half-life of an aldehyde in water.

Biotransformation is perhaps the most important process that will
remove aldehydes from water. It has been shown that both aliphatic
and aromatic aldehydes are biotransformed in the aquatic environment.
In their review of formaldehyde as an environmental contaminant,
Kitchens and co-workers lolf reported evidence that some bacteria in
sewage sludge can use formaldehyde as a sole carbon source and that
complete degradation can be achieved in 48-72 h if the temperatures
and nutrient conditions are maintained. They also cited a study
showing that microorganisms in stagnant lake water could completely
degrade formaldehyde in 30 h at 20C under aerobic conditions and in

107

48 h under anaerobic conditions. That study also showed no detectable
loss of formaldehyde when incubated in sterilized lake water for 48 h.

Bowmer and Higgins 23 reported that acrolein introduced into
water samples from an agricultural area had a half-life of 29 h. When
they reduced microbiologic activity by adding thymol to the water, the
half-life increased to 43 h. Acrolein has been reported to be
effectively biotransformed in activated sewage sludge and in the
biotreatment systems that process the water used by refineries. 31 *

Keith" compared the concentration of several organic compounds
(including four aldehydes) in an effluent from a kraft paper mill
before and after effluent treatment by biodegradation. The treatment
process completely removed benzaldehyde from the effluent and removed
73, 54, and 43% of the vanillin, salicylaldehyde, and synngaldehyde,
respectively.

Although there is ample evidence that aldehydes are oxidizable,
oxidation in the aquatic environment by the alkylperoxyl radical

(R0 2 ) is very slow. The rate constant for this radical in

1 i
abstracting the H atom from the acyl carbon is 0.1 M A s~ , and

Mill 127 estimated the RO2 concentration in the aquatic environment
to be 10~9 M. Assuming that RC>2 addition to the aldehydes is not
important in the liquid phase (although it is important in the gas
phase) , these values indicate that the half-life of aldehydes through
oxidation by the R02 radical will probably be several years.
However, aldehyde reactions with hydroxyl and alkoxyl radicals and
other oxidizing agents are much faster, and these species may account
for additional pathways that should be included. No information is
available to indicate that oxidation of the diol form of the aldehydes
would occur more rapidly or to suggest what other chemical oxidation
processes might affect the persistence of the aldehydes in the natural
waters.

The effect of light on aldehydes in aqueous systems is unknown.
It is likely that aldehydes undergo photolysis in water, but probably
at a lower rate than in the atmosphere, because light is scattered and
diffracted in water, and color and turbidity limit the intensity and
depth of penetration. Hydration of an aldehyde should substantially
retard its photolysis, because hydration will completely destroy the
carbonyl chromophore responsible for light absorption and the
potential for photodecomposition.

SOME IMPORTANT SECONDARY EFFECTS OF ALDEHYDES
IN THE CHEMISTRY OF THE POLLUTED ATMOSPHERE

INFLUENCE OF ALDEHYDES IN PHOTOCHEMICAL SMOG FORMATION

Bufalini and Brubaker 28 showed many years ago that the
irradiation of the simplest aldehyde, formaldehyde, in dilute
N0-N02~air mixtures could induce the NO-to-NO2 conversion and
ozone formation characteristic of photochemical smog. Altshuller et
al. 5 found that the ultraviolet-irradiated aliphatic aldehydes in
the parts-per-million range in NO- and N^-free, dilute mixtures of

108

the olefinic and aromatic hydrocarbons in air induced the
photooxidation of the hydrocarbons. They expressed concern that these
results could modify current considerations of whether control of the
nitrogen oxides would effectively reduce photochemical air pollution.

Using dilute NO-NC>2-aldehyde and/or -hydrocarbon mixtures in
air, Dimitriades and Wesson 57 studied the smog-forming reactivities
of several aldehydes formaldehyde, acetaldehyde , propionaldehyde,
n_-butyr aldehyde, acrolein, crotonaldehyde , benzaldehyde,
o-tolualdehyde, m-tolualdehyde, and p_-tolualdehyde. Several criteria
were used to establish the reactivity of the aldehyde or olefin used:
rate of N02 formation; maximal concentrations of ozone,
peroxyacetylnitrate, peroxybenzoylnitrate, and formaldehyde; and the
time-weighted exposures (ppm x rain) for these four products. These
workers concluded that the aldehydes present in auto exhaust as a
group should be classified among the reactive exhaust components. The
specific reactivity (reactivity per part per million) of formaldehyde,
as measured by the rate of NO-to-NC>2 conversion, was comparable with
that of the average exhaust alkene. However, with respect to oxidant
yield, the specific reactivity of formaldehyde was considerably lower
than that of the average exhaust hydrocarbon. The specific reactivity
of the higher aldehydes was in every respect comparable with that of
the average exhaust alkene. When tested individually, benzaldehyde
and m- and p_-tolualdehyde were unreactive, and o-tolualdehyde was
reactive. In mixtures, benzaldehyde and presumably all the aromatic
aldehydes manifested reactivity as precursors of the strong eye
irritants, the peroxybenzoylnitrates.

Dimitriades and Wesson 57 observed another important effect of
formaldehyde: mixtures containing formaldehyde appeared to have
higher oxidant-yield reactivity than expected from the sum of the
individual effects observed from the specific reactivity and
compositional data alone; the difference increased with increasing
formaldehyde content.

Kopczynski jet aiL. 10B found that the photooxidation of dilute
mixtures of formaldehyde, acetaldehyde, and propionaldehyde in the
presence of nitrogen oxides produces the same products and biologic
effects (eye irritation and plant damage) as does the hydrocarbon
photooxidation. Propionaldehyde was found to be the most reactive,
with respect to highest product yields, eye irritation, and plant
damage. These workers concluded that, inasmuch as aldehydes are both
primary (directly emitted) and secondary (photochemically formed)
products, their substantial reactivities are of special importance.
They may be expected to contribute to photochemical air pollution
problems, not only in the central city, but in the urban, suburban,
and rural areas downwind.

Computer modeling of the complex chemical changes expected to
occur in simulated, sunlight-irradiated, NO-, NO2~r hydrocarbon-,
and aldehyde-polluted atmospheres has confirmed the observed aldehyde
effects and pointed to the specific chemistry responsible for these
effects. 1 " 38 39 * 5S SB 7<l 103 12 139 It has shown that the
aldehydes (formaldehyde and acetaldehyde) present initially in
polluted air will decrease the induction period observed for ozone,

109

peroxyacetylnitrate, and other products formed and their final
concentrations, which increase in simulated smog mixtures.

Jeffries and Kamens 91 * have demonstrated this aldehyde effect in
experiments in a large outdoor smog chamber (Figure 5-12). In matched
experiments carried out in sunlight simultaneously in two equivalent,
isolated portions of the chamber, nearly equivalent amounts of a
typical pollutant composition, hydrocarbon mixture (urban mix) and
nitrogen oxides, were injected, in only one side, additional
acetaldehyde was added initially (about 10% of the nonmethane
hydrocarbon) . The photochemical reactions forming ozone proceeded
faster and significantly higher ozone concentrations developed in the
experiment with additional added acetaldehyde.

Pitts et^ al^ llt9 have observed a similar effect in smog-chamber
photooxidation experiments with a surrogate mixture of hydrocarbons
with and without added formaldehyde (Figure 5-13) . The initial rate
of ozone formation and the final ozone concentration reached during
the experiment both were increased greatly by the addition of small
amounts of formaldehyde.

The reactions that determine the influence of the aldehydes in
these simulated smog mixtures are largely those already described:
radical formation through photodecomposition of the aldehydes and the
reactions of the HO radical with the aldehydes. The ozone
concentration developed in the NO^- and RH-polluted,
sunlight-irradiated atmosphere is related to the NO 2 -to-NO ratio, as
a result of the following rapid reactions involving NO, NO 2 r and
ozone:

N0 2 + hy + NO + (34)

+ 2 (+N 2 , 2 ) - 3 (+N 2 , 2 ) (35)

O 3 + NO - 2 + N0 2 (36)

For the usual conditions in these highly polluted atmosphere, one
expects Equation 37 to hold approximately: 35 36 112

[0 3 ] ([N0 2 ]/[NO]) (k 34 /k 36 ) (37)

The presence of the aldehydes can provide an additional source of the
hydroperoxy (H0 2 ) and alkylperoxy radicals (CH 3 2 , C 2 H 5 O 2 ,
RO 2 , etc.), which may pump NO to N0 2 and hence increase the ozone
concentration through its close relation to the [N0 2 J/[NO] ratio:

RCHO + hu R + HCO (38)

R + 2 - R0 2 (39)

HCO + 2 * H0 2 + CO (23)

R0 2 + NO RO + N0 2 (40)

H0 2 + NO + HO + NO 2 (41)

110

.500

1 I ' I ' I ' I ' I ' I ' I ' I ' I ' I ' 1 ' I ' I -

SEPTEMBER 2<f, 1976 _

E
O.
O.

01

O

O

z

.400 -

.300 -

.200 -

.100 -

NO

.000

> i . i . i , j

^_ i .1.1,1

_

5 6 7 8 9 10 11 12 13 H 15 16 17 IB 19

HOURS. EOT

FIGURE 5-12 Comparison of nitric oxide, nitrogen dioxide, and ozone
profiles in urban mix with (solid lines) and without (dashed lines)
additional added acetaldehyde (10% of initial nonmethane hydrocarbon
concentration). Initial conditions: with added acetaldehyde, NO ,
0.325 ppm, urban mix, 2.32 ppmC; without added acetaldehyde, NO ,
0.332 ppm, urban mix* 2.45 ppmC. Reprinted with permission from
Jeffries and Kamens.

Ill

I ' I

AV NMHC = 2450ppbC

05

AV NO

TIME (hours)

FIGURE 5-13 Effect of added formaldehyde on ozone formation
in irradiation of surrogate mixtures of hydrocarbons and
nitrogen oxides. Reprinted with permission from Pitts ^t al.

149

112

The alkoxy (RO) and hydroxyl radicals formed in Reactions 40 and 41
can regenerate HC>2 and RO 2 radicals in further reactions with the
impurity aldehydes, as well as the hydrocarbons present:

HO + HCHO

* H 2 + HCO

HCO + 2

->. H0 2 + CO

HO + RCHO

+ RCO + H20

RCO + 02

- RCO0 2

RC00 2 + NO

-. RC0 2 + N0 2

RC02

* R + C0 2

R + 2

* R02

(26)
(23)
(42)
(43)
(44)
(45)
(39)

Obviously, the aldehydes provide a new route for a chain reaction
driving NO to N02 in these systems, and hence they can influence the
generation of ozone in photochemical smog. It is clear that the
control of aldehyde emission, as well as hydrocarbon emission, is
important in the strategy for ozone control.

THE INFLUENCE OF ALDEHYDES ON THE FORMATION OF PEROXYACYLNITRATES IN
THE POLLUTED ATMOSPHERE

The aliphatic and aromatic aldehydes are important precursors of
the notorious peroxyacylnitrates and peroxybenzoylnitrates. For
example, all the experimental evidence and theoretical considerations
support the view that acetaldehyde is a direct precursor of
peroxyacetylnitrate (PAN) in the real atmosphere: 55

CH 3 CHO + HO -f CH 3 CO + H 2 O (46)

CH 3 CO + 2 -> CH 3 C00 2 (47)

CH3C002 + N02 - CH3COO 2 NO2 (PAN) (48)

NO -- CH3C0 2 + N0 2 (49)

Similar reactions presumably lead to the formation of the higher
homologues of PAN in the case of the higher aliphatic aldehydes
(propionaldehyde, etc.) 68 and the aromatic aldehydes (benzaldehyde,
etc.). 85 (Gay et_ ajL_. 68 cited references to the earlier studies
of the peroxyacylnitrates.) The simplest member of the aldehyde
family, formaldehyde, does not form the analogous peroxyformylnitrate,
HC00 2 N0 2 , in substantial amounts; presumably, this is a
consequence of the unique disproportionate of the HCO radical with

113

2 , which dominates the association reaction (Reaction 50) in this
case:

HCO + 2 - HO 2 + CO (23)

HCO + 2 (+N 2 or 2 ) - HCOO 2 (+N 2 or 2 ) (50)

However, in the photooxidation of formaldehyde in N0 2 -containing
mixtures, the less stable peroxynitric acid, H0 2 NO 2 , results from
the H0 2 reaction with N0 2 : 7e 1 "

H0 2 +N0 2 ^H0 2 N0 2 (51)

We may conclude that the presence of the aldehydes or their
precursors (hydrocarbons) in the polluted atmosphere is directly
involved in the formation of the important class of highly oxidizing,
eye-irritating secondary pollutants, the peroxyacylnitrates and the
peroxybenzoylnitrates .

THE POTENTIAL ROLE OF FORMALDEHYDE IN THE ORIGIN OF FORMIC ACID IN THE
POLLUTED ATMOSPHERE

The gas-phase photooxidation of formaldehyde at low concentrations
in air has been shown to lead to the products H 2 O 2 , CO, CO 2 ,
H 2 , and HC0 2 H. 28 89 l * llt7 Recently, H0 2 CH 2 OH has been
identified as an intermediate product of this system, l72 and its
reaction to form formic acid was noted. The kinetic results suggest
that the reaction of H02 addition to formaldehyde leads to this new
product. Other recent experiments with C 2 H^ , 0^ , and
formaldehyde mixtures at parts-per-million concentrations in air
showed that the reactive CH 2 O2 intermediate product from the
C 2 H 4~3 reaction may lead to formic acid as well. 170 In this
case, an unidentified intermediate is formed first by
CH 2 02~formaldehyde reaction; this leads to formic acid anhydride
and hence to formic acid; a possible reaction scheme consistent with
the kinetics is the following:

C 2 H 2 + 3 * CH 2 O 2 + HCHO (52)

0-0
CH 2 2 +HCHO->CH 2 OOCH 2 O- CH 2 CH 2 - (53)

x o x

OCH 2 OCH 2 O - HOCH 2 OCHO

O

(I II
HOCH 2 OCHO -> H 2 + HCOCH (54)

114

HCOCH + H 2 O(aerosol) -> 2HCO 2 H (55)

These newly discovered reaction routes to formic acid may explain,
at least in part, the large amount of formic acid identified in aged,
highly polluted atmospheres. 178 Conceivably, the apparent
correlation of formaldehyde content of smog mixtures with eye
irritation 3 85 195 is related in part to the HC02H formation, which
would follow roughly the formaldehyde concentration in these systems
through the reactions outlined.

THE POTENTIAL ROLE OF FORMALDEHYDE IN THE GENERATION OF

BIS (CHLOROMETHYL) ETHER IN HYDROGEN CHLORIDE-FORMALDEHYDE-POLLUTED

ATMOSPHERES

It has been observed that bis (chloromethyl) ether (BCME) is formed
from moist air containing formaldehyde and hydrogen chloride gases. 63
98 157 T h e overall reaction is:

2HC1 + 2HCHO ^ C1CH 2 OCH 2 Cl + H 2 (56)

Studies by Drew et, al. , 59 Laskin et al. x l and Kuschner et al. 1 9
have shown that the chloromethyl ethers are respiratory tract
carcinogens, and epidemiologic studies have indicated that they are
human carcinogens. 1 In a recent study, 157 it was demonstrated that
Reaction 56 occurred under dynamic conditions at room temperature with
relatively high formaldehyde and HC1 concentrations in the gas
phase about 1,000 and 6,500 ppm, respectively. Chronic exposure of
rats to dilute HCl-formaldehyde-chloromethyl ether mixtures
bis (chloromethyl) ether at about 2.8 ppb, HC1 at 10.7 ppm, and
formaldehyde at 14.6 ppm caused a markedly increased incidence of
squamous metaplasia of the nasal cavity and squamous cell carcinoma of
the nasal epithelium after 136-390 d.

From the very limited data at hand, it is impossible to extrapolate
with great confidence to the lower, more representative concentrations
of bis {chloromethyl) ether that would be formed with the HC1 and
formaldehyde concentrations commonly encountered in the atmosphere.
However, we can derive present "best" estimates from both experimental
and theoretical data on the HCHO-HC1-C1CH20CH2C1 system. The
reaction kinetics of the chloromethyl ether formation has not been

determined. But, for a worst-case estimate, we may assume that an
equilibrium concentration of the ether is formed in the atmosphere;
this will overestimate the actual concentrations somewhat. We may make
the reasonable assumption that equilibrium was achieved at the longest
reaction times used in the experiments of Sellakumar e^^l- 157 and
Frankel et^al^ 63 These data give: K^g

*600 300 atirT 2 , where K 56 = (P^Q) (PBCME>/ 0?HC1> 2 < P HCHO> 2 '
and PBCME i s tJ:ie pressure of the bis (chloromethyl) ether.

115

A rough check may be made on the reasonableness of the 1(5 g
estimate derived from the experiments. We may use the estimated
enthalpy and entropy changes for Reaction 56 , AH56 and AS 5g,
to derive a theoretical estimate of K^gt K^g =
e ^/R e -AH/RT > Benson's 2 approximate thermochemical
methods may be used to derive the unknown thermodynamic quantities for
the bis (chloromethyl) ether: AH f a -58.4 3 kcal/mol, S
86.4 2 cal mol" 1 deg" 1 (25C, 1 atm) . Coupling these
quantities with the measured experimental enthalpies of formation and
absolute entropies of the other reactants and products, we calculate
the theoretical range of values, which should include K5g: 6,580 >
K56 > 0.036 atm~2. As one anticipates if the approach in
estimating Kgg is reasonable, the experimental value is within this
range. Thus, one might use these data to obtain reasonable,
order-of-magnitude results for the concentrations of bis (chloromethyl)
ether in polluted atmospheres.

We have used the maximal concentrations of formaldehyde observed
in the urban atmosphere (about 0.10 ppm) and a seemingly reasonable
maximum for hydrogen chloride (about 10 ppb) in air at 50% relative
humidity at 25C.* Using the upper limit estimated for K5g, 6,580
atm"~2, we estimate the maximal equilibrium concentration of
bis (chloromethyl) ether for these conditions at about 4 x 10" 1 "
ppb. Thus, we may conclude tentatively that there is probably little
impact on human health from the generation of bis (chloromethyl) ether
from formaldehyde and HC1 in the urban atmosphere.
We must be cognizant of the potential hazard under conditions more
favorable to bis (chloromethyl) ether formation. Thus, in principle,
this compound could be formed in HCl-rich plumes from the incineration
of polyvinyl chloride or other HCl-producing processes in which
formaldehyde may be present at a high concentration. The potential
for bis (chloromethyl) ether generation exists if fairly concentrated
HC1 solutions are brought into contact with formaldehyde-containing
particleboard or other formaldehyde-copolymer materials. Such
polymers may contain free formaldehyde or they may hydrolyze to form
formaldehyde and then interact with HC1 to lead to C1CH20CH2C1.
There is no evidence of which the Committee is aware that allows an
evaluation of these potential problems.

Further direct tests for bis (chloromethyl) ether in the ambient
air and water and new and more precise measurements of K$$ and the
rate-determining reactions that control its rates of formation and
decay are required, in order to evaluate quantitatively the potential
extent of human exposure to and the influence of bis (chloromethyl)
ether.

*This estimate of HC1 concentration is about 10 times the number
estimated theoretically for the "clean" lower troposphere by the
Livermore Kinetic-Transport Model, from which [HC1] =0.9 ppb (D.J.
Wuebbles, personal communication, 1979). It is also somewhat greater
than the highest concentrations observed in ambient air near the
ground. 61 69 9G 97

116
REFERENCES

1. Albert, R. , B. Pasternak, R. Shore, M. Lippmann, N. Nelson, and
B. Ferris. Mortality patterns among workers exposed to
chloromethyl ethers A preliminary report. Environ. Health
Perspect. 2:209-214, 1975.

2. Allan, G. G., J. Dutkiewicz, and E. J. Gilmartin. Long-term
stability of urea-formaldehyde foam insulation. Environ. Sci.
Technol. 14:1235-1240, 1980.

3. Altshuller , A. P. Assessment of the contribution of chemical
species to the eye irritation potential of photochemical smog.
J. Air Pollut. Control Assoc. 28:594-598, 1978.

4. Altshuller, A. P., and I. R. Cohen. Photo-oxidation of
acrolein-nitrogen oxide mixtures in air. Int. J. Air Water
Pollut. 7:1043-1049, 1963.

5. Altshuller, A. P., I. R. Cohen, and T. C. Purcell.
Photooxidation of hydrocarbons in the presence of aliphatic
aldehydes. Science 156:937-939, 1967.

6. Altshuller, A. P., L. J. Leng, and A. F. Wartburg. Source and
atmospheric analyses for formaldehyde by chromotropic acid
procedures. Int. J. Air Water Pollut. 6:381-385, 1962.

7. Altshuller, A. P., and S. P. McPherson. Spectrophotometric
analysis of aldehydes in the Los Angeles atmosphere. J. Air
Pollut. Control Assoc. 13:109-111, 1963.

8. Andersen, I., G. R. Lundqvist, and L. M^lhave. Formaldehyde in
the atmosphere in Danish homes. Ugeskr. Laeg. 136:2133-2139,
1974. (in Danish; English summary)

9. Andersen, I., G. R. Lundqvist, and L. Molhave. Indoor air
pollution due to chipboard used as construction material.
Atmos. Environ. 9:1121-1127, 1975.

10. Atkinson, R. , K. R. Darnall, A. C. Lloyd, A. M. Winer, and J. N.
Pitts, Jr. Kinetics and mechanisms of the reactions of the
hydroxyl radical with organic compounds in the gas phase. Adv.
Photochem. 11:375-487, 1979.

11. Atkinson, R. , and J. N. Pitts, Jr. Kinetics of the reactions of
the OH radical with HCHO and CE^CEO over the temperature range
299-426K. J. Chem. Phys. 68:3581-3584, 1978.

12. Bachraan, K. C., and E. L. Kayle. Reactive exhaust emissions
from a stratified-charge engine vehicle. Presented at American
Chemical Society Meeting, Philadelphia, Pa., April 6-11, 1975.
Am. Chem. Soc. Div. Pet. Chem. Preprints 20 (3) : 652-658, 1975.

13. Baker, R. E., J. A. Harrington, J. H. Baudino, L. C. Copeland,
W. J. Koehl, L. J. McCabe, and W. T. Wotring. Utilization of
methanol as an automotive fuel. A report from IIEC-2, the
Inter-Industry Emission Control Program, pp. 2. 7.1. -2. 7. 8. In
Proceedings of the International Symposium on Alcohol Fuel
Technology: Methanol and Ethanol, Wolfsburg, F.R. Germany,
November 21-23, 1977. Washington, D.C.: U.S. Department of
Energy, 1978.

117

14. Baldwin, A. C., J. R. Barker, D. M. Golden, and D. G. Hendry.
Photochemical smog. Rate parameter estimates and computer
simulations. J. Phys. Chem. 81:2483-2492, 1977.

15. Barbe, A., p. Marche, C. Secroun, and p. Jouve. Measurements of
tropospheric and stratospheric E^CO by an infrared high
resolution technique. Geophys. Res. Lett. 6:463-465, 1979.

16. Bass, A. M. , L. C. Glasgow, C. Miller, J. P. Jesson, and D. L.
Filkin. Temperature dependent absorption cross-sections for
formaldehyde (CE^O) : The effect of formaldehyde on
stratospheric chlorine chemistry, pp. 467-477. in Proceedings
of the NATO Advanced Study Institute on Atmospheric Ozone. Its
Variation and Human Influences. Washington, D.C.: U.S.
Department of Transportation, Federal Aviation Administration,
1980.

17. Bell, R. P. The reversible hydration of carbonyl compounds.
Adv. Phys. Org. Chem. 4:1-29, 1966.

18. Bell, R. P., and A. 0. McDougall. Hydration equilibria of some
aldehydes and ketones. Trans. Faraday Soc. 56:1281-1285, 1960.

19. Bengtson, G. W. , and G. K. Voigt. A greenhouse study of
relations between nutrient movement and conversion in a sandy
soil and the nutrition of slash pine seedlings. Soil Sci. Soc.
Am. Proc. 26:609-612, 1962.

20. Benson, S. W. Thermochemical Kinetics. Methods for the
Estimation of Thermochemical Data and Rate Parameters. 2nd ed.
New York: John Wiley & Sons, 1976. 320 pp.

21. Berger, V., and M. Tomas. Urea-formaldehyde resins with a low
content of free formaldehyde. Drevo 19:211-214, 1964. (in Czech)

22. Blejer, H. P., and B. H. Miller. Occupational Health Report of
Formaldehyde Concentrations and Effects on Workers at the Bayly
Manufacturing Company, Visalia. Study Report S-1806. Los
Angeles: State of California Health and Welfare Agency, Dept.
of Public Health, Bureau of Occupational Health, 1966. 6 pp.

23. Bowmer, K. H., and M. L. Higgins. Some aspects of the
persistence and fate of acrolein herbicide in water. Arch.
Environ. Con tarn. Toxicol. 5:87-96, 1976.

24. Braslavsky, S., and J. Heicklen. The gas-phase reaction of O 3
with H 2 CO. Int. J. Chem. Kinet. 8:801-808, 1976.

25. Breeding, R. J-, J. P. Lodge, Jr., J. B. Pate, D. C. Sheesley,
H. B. Klonis, B. Fogle, J. A. Anderson, T. R. Englert, P. L.
Haagenson, R. B. McBeth, A. L. Morris, R. Pogue, and A. F.
Wartburg. Background trace gas concentration in the central
United States. J. Geophys. Res. 78:7057-7064, 1973.

26. Breysse, P. A. The environmental problems of urea-formaldehyde
structures. Formaldehyde exposure in mobile homes. Presented
at American Medical Association Congress on Occupational Health,
26 Oct. 1979.

27. Brinkman, N. D. Effect of Compression Ratio on Exhaust
Emissions and Performance of a Methanol-Fueled Single-Cylinder
Engine. SAE Paper No. 770791. Warrendale, Pa.: Society of
Automotive Engineers, Inc. 16 pp.

118

28. Bufalinir J- JT and K - L - Brubaker. The photooxidation of
formaldehyde at low partial pressures, pp. 225-240. In C. S.
Tuesday, Ed. Chemical Reactions in Urban Atmospheres. Symposium
Held at the General Motors Research Laboratories, Warren,
Michigan, 1969. New York: American Elsevier Publishing
Company, Inc., 1971.

29. Bykowski, B. B. Gasohol, TBA, MTBE Effects on Light-Duty
Emissions. Final Report of Task Force 6, Contract 68-03-2377.
San Antonio, Texas: Southwest Research Institute, October 1979.

30. Cadle, R. D., S. S. Lin, and R. F. Hausman, Jr. The reaction of
0( 3 P) with propionaldehyde and acrolein in a fast-flow

system. Chemosphere 1:15-20, 1972.

31. Cadle, R. D. , and J. W. Powers. The reaction of 0( 3 P) with
acetaldehyde in a fast- flow system. J. Phys. Chem.
71:1702-1706, 1967.

32. Cadle, S. H. , G. J. Nebel, and R. L. Williams. Measurements of
Unregulated Emissions from General Motors' Light-Duty Vehicles.
SAE Paper No. 790694. Warrendale, Pa.: Society of Automotive
Engineers, Inc., 1979. 21 pp.

33. California Air Resources Board. Staff Report. 1972.

34. Callahan, M. A., M. W. Slimak, N. W. Gabel, I. P. May, C. F.
Fowler, J. R. Freed, P. Jennings, R. L. Durfee, F. C. Whitmore,
B. Maestri, W. R. Mabey, B. R. Holt, and C. Gould.
Water-Related Environmental Fate of 129 Priority Pollutants.
Vol. II. Halogenated Aliphatic Hydrocarbons, Halogenated
Ethers, Monocyclic Aromatics, Phthalate Esters, Polycyclic
Aromatic Hydrocarbons, Nitrosamines, and Miscellaneous
Compounds. U.S. Environmental Protection Agency Report No.
EPA-440/4-79-029b. Washington, D.C.: U.S. Environmental
Protection Agency, Office of Water Planning and Standards,
1979. [714] pp.

35. Calvert, J. G. Hydrocarbon involvement in photochemical smog
formation in Los Angeles atmosphere. Environ. Sci. Technol.
10:256-262, 1976.

36. Calvert, J. G. Test of the theory of ozone generation in Los
Angeles atmosphere. Environ. Sci. Technol. 10:248-256, 1976.

37. Calvert, J. G. The homogeneous chemistry of formaldehyde
generation and destruction within the atmosphere, pp. 153-190.
In Proceedings of the NATO Advanced Study Institute on
Atmospheric Ozone: Its Variation and Human Influences.
Washington, D.C.: U.S. Department of Transportation, Federal
Aviation Administration, 1980.

38. Calvert, J. G., K. L. Demerjian, J. A. Kerr. Computer
simulation of the chemistry of a simple analogue to the
sunlight-irradiated auto-exhaust polluted atmosphere. Environ.
Lett. 4:123-140, 1973.

39. Calvert, J. G., and R. D. McQuigg. The computer simulation of
the rates and mechanisms of photochemical smog formation, pp.
113-154. in S. W. Benson, D. M. Golden, and J. R. Barker, Eds.
Proceedings of the Symposium on Chemical Kinetics Data for the
Upper and Lower Atmosphere. Held at Warrenton, Virginia,

119

September 15-18, 1974. Published as a book supplement to Int.
J. Chera. Kinet. 7. New York: John Wiley & Sons, Inc., 1975.

40. Calvert, J. G., and J. N. Pitts, Jr. Photochemistry. New
York: John Wiley & Sons, Inc., 1966. 899 pp.

41. Calvert, J. G., P. Su, J. W. Bottenheim, and O. P. Strausz.
Mechanism of the homogeneous oxidation of sulfur dioxide in the
troposphere. Atmos. Environ. 12:197-226, 1978.

42. Carter, W. P. L., A. C. Lloyd, J. L. Sprung, and J. N. Pitts,
Jr. Computer modeling of smog chamber data: Progress in
validation of a detailed mechanism for the photooxidation of
propene and n_-butane in photochemical smog. Int. J. Chem.
Kinet. 11:45-101, 1979.

43. Cauler, H. Some problems of atmospheric chemistry. In
Compendium of Meteorology. Baltimore: Waver ly Press, Inc. ,
1951.

44. Chang, J. S., and J. R. Barker. Reaction rate and products for
the reaction O( 3 P) + H 2 CO. J. Phys. Chem. 83:3059-3064, 1979.

45. Chui, G. K., R. D. Anderson, R. E. Baker, and F. B. P. Pinto.
Brazilian vehicle calibration for ethanol fuels. Paper 11-17.
Proceedings of Third International Symposium on Alcohol Fuels
Technology, Asilomar, Cal., May 29, 1979. 10 pp. Washington,
D.C.: U.S. Department of Energy, 1980.

46. Cleveland, W. S., T. E. Graedel, and B. Kleiner. Urban
Formaldehyde: Observed correlation with source emissions and
photochemistry. Atmos. Environ. 11:357-360, 1977.

47. Coleman, W. E., R. D. Lingg, R. G. Melton, and F. C. Kopfler.
The occurrence of volatile organics in five drinking water
supplies using gas chromatography/mass spectrometry, pp.
305-327. In L. H. Keith, Ed. Identification and Analysis of
Organic Pollutants in Water. Ann Arbor, Mich.: Ann Arbor
Science Publishers, Inc., 1976.

48. Cox, R. A., R. G. Derwent, P. M. Holt, and J. A. Kerr.
Photolysis of nitrous acid in the presence of acetaldehyde. J.
Chem. Soc., Faraday Trans. I 72:2061-2075, 1976.

49. Crutzen, P. J. , and J. Fishman. Average concentrations of OH in
the troposphere, and the budgets of CH4 , CO, H2 r and

CH 3 CC1 3 . Geophys. Res. Lett. 4:321-324, 1977.

50. Cvetanovic, R. J. Reaction of oxygen atoms with acetaldehyde.
Can. J. Chem. 34:775-784, 1956.

51. Darley, E. P., J. T. Middleton, and M. J. Garber. Plant damage
and eye irritation from ozone-hydrocarbon reactions. Agric.
Food Chem. 8:483-485, 1960.

52. Davis, D. D. OH Radical Measurements: Impact on Power Plant
Plume Chemistry. Electric Power Research Institute Report No.
EA-465. Palo Alto: Electric Power Research Institute, 1977.
60 pp.

53. Davis, D. D. , W. Heaps, and T. McGee. Direct measurements of
natural tropospheric levels of OH via an aircraft borne tunable
dye laser. Geophys. Res. Lett. 3:331-333, 1976.

120

54. Deimel, M. Erfahrungen uber Formaldehyd Raumluft -Konzen-
trationen in Schulneubauten. Presented at the Conference on
Organic Pollution in Indoor and Outdoor Air, Berlin, 1976.

55. Demerjian, K. L., J. A. Kerr, and J. G. Calvert. The mechanism
of photochemical smog formation. Adv. Environ. Sci. Technol.
4:1-262, 1974.

56. Demerjian, K. L., K. L. Schere, and J. T. Peterson. Theoretical
estimates of actinic (spherically integrated) flux and
photolytic rate constants of atmospheric species in the lower
troposphere. Adv. Environ. Sci. Technol. 10:369-459, 1980.

57. Dimitriades, B., and T. C. Wesson. Reactivities of exhaust
aldehydes. J. Air Pollut. Control Assoc. 22:33-38, 1972.

58. Dodge, M. C., and T. A. Hecht. Rate constant measurements
needed to improve a general kinetic mechanism for photochemical
smog, pp. 155-163. In S. W. Benson, D.M. Golden, and J. R.
Barker, Eds. Proceedings of the Symposium on Chemical Kinetics
Data for the Upper and Lower Atmosphere. Held at Warrenton,
Virginia, September 15-18, 1974. Published as a book supplement
to Int. J. Chera. Kinet. 7. New York: John Wiley & Sons, Inc.,
1975.

59. Drew, R. T. , S. Laskin, M. Kuschner, and N. Nelson. The
inhalation carcinogenicity of alpha halo ethers. I. The acute
inhalation toxicity of chloromethyl methyl ether and
bis(chloromethyl) ether. Arch. Environ. Health 30:61-69, 1975.

59a. Ewing, B. B., E. S. K. Chian, J. C. Cook, C. A. Evans, and P. K.
Hopke. Monitoring to Detect Previously Unrecognized Pollutants
in Surface Waters Appendix: Organic Analysis Data. U.S.
Environmental Protection Agency Report No. EPA-560/6-77-015a.
Washington, D.C.: U.S. Environmental Protection Agency, 1977.
304 pp.

60. Fanning, L. Z. Formaldehyde in Office Trailers. Lawrence
Berkeley Laboratory Report No. LBID-084. Berkeley, California:
Lawrence Berkeley Laboratory, Energy and Environment Division,
26 October 1979. 7 pp.

61. Farmer, C. B., O. F. Raper, B. D. Robbins, R. A. Toth, and C.
Muller. Simultaneous spectroscopic measurements of
stratospheric species: 3 , CH 4 , CO, C0 2 , N 2 0, H 2 0,

HC1, and HF at northern and southern mid-latitudes. J. Geophys.
Res. 85:1621-1632, 1980.

62. Fox, M. E. Fate of selected organic compounds in the discharge
of Kraft paper mills into Lake Superior, pp. 641-659. In L. H.
Keith, Ed. Identification and Analysis of Organic Pollutants in
Water. Ann Arbor, Mich.: Ann Arbor Science Publishers, Inc.,
1976.

63. Frankel, L. S., K. S. McCallum, and L. Collier. Formation of
bis (chloromethyl) ether from formaldehyde and hydrogen chloride.
Environ. Sci. Technol. 8:356-359, 1974.

64. Freeman, H. G., and W. C. Grendon. Formaldehyde detection and
control in the wood industry. Forest Prod. J. 21 (9): 54-57, 1971,

65. Gaffney, J. S., R. Atkinson, and J. N. Pitts, Jr. Relative rate
constants for the reaction of O( 3 P) atoms with selected

121

olefins, monoterpenes , and unsaturated aldehydes. J. Araer .
Chem. Soc. 97:5049-5051, 1975.

66. Gamble, J. P., A. J. McMichael, T. Williams, and M. Battigelli.
Respiratory function and symptoms: An environmental
epidemiological study of rubber workers exposed to a
phenol-formaldehyde type resin. Am. Ind. Hyg. Assoc. J.
37:499-513, 1976.

67. Garry, V. P., L. Oatman, R. Pleus, and D. Gray. Formaldehyde in
the home. Some environmental disease perspectives. Minn. Med.
63:107-111, 1980.

68. Gay, B. W. , Jr., R. C. Noonan, J. J. Bufalini, and P. L. Hanst.
Photochemical synthesis of peroxyacyl nitrates in gas phase via
chlorine-aldehyde reaction. Environ. Sci. Technol. 10:82-85,
1976.

69. Georgii, H.-W. Untersuchungen uber AtmosphSnsche Spurenstoffe
und ihre Bedeutung fur die Chemie der Niederschlage. Geofis.
Pura Appl. 47:155-171, 1960.

70. Gerstle, R. W. , and D. A. Kemnitz. Atmospheric emissions from
open burning. J. Air Pollut. Control Assoc. 17:324-327, 1967.

71. Gibbard, S., and R. Schoental. Simple semi-quantitative
estimation of sinapyl and certain related aldehydes in wood and
in other materials. J. Chromat. 44:396-398, 1969.

72. Giger, W. , M. Reinhard, C. Schaffner, and F. Ziircher. Analyses
of organic constituents in water by high-resolution gas
chromatography in combination with specific detection and
computer-assisted mass spectrometry, pp. 433-452. In L. H.
Keith, Ed. Identification and Analysis of Organic Pollutants in
Water. Ann Arbor, Mich.: Ann Arbor Science Publishers, Inc.,
1976.

73. Graedel, T. E. Chemical Compounds in the Atmosphere. New York:
Academic Press, Inc., 1979. 440 pp.

74. Graedel, T. E., L. A. Farrow, and T. A. Weber. The influence of
aerosols on the chemistry of the troposphere, pp. 581-594. In
S. W. Benson, D. M. Golden, and J.R. Barker, Eds. Proceedings
of the Symposium on Chemical Kinetics Data for the Upper and
Lower Atmosphere. Held at Warren ton, Virginia, September 15-18,
1974. Published as a book supplement to Int. J. Chem. Kinet. 7.
New York: John Wiley & Sons, Inc., 1975.

75. Grob, K. Organic substances in potable water and in its
precursor. Part I. methods for their determination by
gas-liquid chromatography. J. Chromat. 84:255-273, 1973.

76. Hagin, J., and L. Cohen. Nitrogen fertilizer potential of an
experimental urea formaldehyde. Agron. J. 68:518-520, 1967.

77. Hangebrauck, R. P., D. J. von Lehmden, and J. E. Meeker.
Emissions of polynuclear hydrocarbons and other pollutants from
heat-generation and incineration processes. J. Air Pollut.
Control Assoc. 14:267-278, 1964.

78. Hanst, P. L., and B. W. Gay, Jr. Photochemical reactions among
formaldehyde, chlorine, and nitrogen dioxide in air. Environ.
Sci. Technol. 11:1105-1109, 1977.

122

79. Hanst, P. L. , W. E. Wilson, R. K. Patterson, B. W. Gay, Jr., L.
W. Chaney, and C. S. Burton. A spectroscopic study of
California smog, pp. 17-70. In Proceedings of the 6th Annual
Symposium. Trace Analysis and Detection in the Environment, 29
April-1 May, 1975. Edgewood Arsenal Special Report
EO-SP-76001. Aberdeen Proving Ground, Md.: Edgewood Arsenal
1975.

80. Harke, H.-P., A. Baars, B. Frahm, H. Peters, and C. Schultz.
The problem of passive smoking. Concentration of smoke
constituents in the air of large and small rooms as a function
of number of cigarettes smoked and time. Int. Arch.
Arbeitsmed. 29:323-339, 1972. (in German; English summary)

81. Harrington, J. A., D. D. Brehob, and E. H. Schanerberger .
Evaluation of methyl tertiary-butyl ether as a gasoline blending
component. Paper 111-53, pp. 1-13. In Proceedings of Third
International Symposium on' 1 Alcohol Fuels Technology, Asilomar,
Cal., May 29, 1979. Washington, D.C.: U.S. Department of
Energy, 1980.

82. Harris, D. K. Health problems in the manufacture and use of
plastics. Br. J. Ind. Med. 10:255-268, 1953.

83. Herron, J. T., and R. E. Huie. Rate constants for the reactions
of ozone with ethene and propene, from 235.0 to 362.0 K. J.
Phys. Chem. 78:2085-2088, 1974.

84. Herron, J. T., and R. D. Penzhorn. Mass spectrometric study of
the reactions of atomic oxygen with ethylene and formaldehyde.
J. Phys. Chem. 73:191-196, 1969.

85. Heuss, J. M. , and W. A. Glasson. Hydrocarbon Reactivity and Eye
Irritation. Environ. Sci. Technol. 2:1109-1116. 1968.

86. Hollowell, C. D., J. V. Berk, M. L. Boegel, R. R. Miksch, W. W.
Nazaroff, and G. W. Traynor. Building Ventilation and Indoor
Air Quality. Lawrence Berkeley Laboratory Report LBL-10391.
Berkeley, Cal.: Lawrence Berkeley Laboratory, for U.S.
Department of Energy, 1980. 12 pp.

87. Horowitz, A., and J. G. Calvert. The quantum efficiency of the
primary processes in formaldehyde photolysis at 3130 A and
25C. Int. J. Chem. Kinet. 10:713-732, 1978.

88. Horowitz, A., and J. G. Calvert. Wavelength dependence of the
quantum efficiencies of the primary processes in formaldehyde
photolysis at 25C. Int. J. Chem. Kinet. 10:805-819, 1978.

89. Horowitz, A., F. Su, and J. G. Calvert. Unusual H 2 -forming
chain reaction in the 3130 A photolysis of formaldehyde-oxygen
mixtures at 25C. Int. J. Chem. Kinet. 10:1099-1117, 1978.

90. Huie, R. E., and J. T. Herron. Temperature dependence of the
rate constants for reactions of ozone with some olefins. int.
J. Chem. Kinet. 7 (Suppl. ): 165-181, 1975.

91. Jackson, M.W. Effect of catalytic emission control on exhaust
hydrocarbon composition and reactivity. SAE Paper No. 780624.
Warrendale, Pa.: Society of Automotive Engineers, Inc. 1978.
24 pp.

123

92. Jaffee, S., and E. Wan. Thermal and photochemical reactions ot
NC>2 with butyraldehyde in gas phase. Environ. Sci. Technol.
8:1024-1025, 1974.

93. Jeffries, H. E., and R. M. Kamens. A Critical Review of Ambient
Air Aldehyde Measurement Methods and an Analysis of Houston
Aldehyde Data. Part II. An Analysis of Houston Aldehyde Data
and Comparison with Cincinnati and St. Paul Data. Prepared for
Houston Area Oxidant Study. Chapel Hill, N.C.: University of
North Carolina School of Public Health, 1977.

94. Jeffries, H. E., and R. M. Kamens. Outdoor Simulation of Air
Pollution Control Strategies. Progress Report for 1975-1976.
U.S. Environmental Protection Agency Grant 800916. Chapel Hill,
N.C.: University of North Carolina, School of Public Health,
1977.

95. Jermini, C., A. Weber, and E. Grandjean. Quantitative
determination of various gas-phase components of the side-stream
smoke of cigarettes in the room air as a contribution to the
problem of passive smoking. Int. Arch. Occup. Environ. Health
36:169-181, 1976. (in German)

96. Junge, C. E. Chemical analysis of aerosol particles and gas
traces on the island of Hawaii. Tellus 9:528-537, 1957.

97. Junge, C. E. Recent investigations in air chemistry. Tellus
8:127-139, 1956.

98. Kallos, G. J., and R. A. Solomon. Investigations of the
formation of bis (chloromethyl) ether in simulated hydrogen
chloride-formaldehyde atmospheric environments. Amer. Ind. Hyg.
Assoc. J. 34:469-473, 1973.

98a. Katou, T. Research of the smog materials in the atmosphere by

CG method, pp. 419-425. In Proceedings. International Symposium
on Air Pollution 1972 Tokyo. The Status of Air Pollution and
the Progress of the Preventive Technology. Tokyo: Union of
Japanese Scientists and Engineers, 1972.

99. Keith, L. H. GC/MS analysis of organic compounds in treated
Kraft paper mill wastewaters, pp. 671-707. In L. H. Keith, Ed.
Identification and Analysis of Organic Pollutants in Water. Ann
Arbor, Mich.: Ann Arbor Sciences Publishers, Inc., 1976.

100. Keith, L. H. , A. W. Garrison, F. R. Allen, M. H. Carter, T. L.
Floyd, J. D. Pope, and A. D. Thruston, Jr. Identification of
organic compounds in drinking water' from thirteen U.S. cities,
pp. 329-373. In L. H. Keith, Ed. Identification and Analysis
of Organic Pollutants in Water. Ann Arbor, Mich.: Ann Arbor
Science Publishers, Inc., 1976.

101. Kelly, M. W. Critical Literature Review of Relationships
between Processing Parameters and Physical Properties of
Particleboard. General Technical Report FPL-10 . Madison,
Wise.: U.S. Department of Agriculture, Forest Service, Forest
Products Laboratory, 1977. 69 pp.

102. Kerfoot, E. J., and T. F. Mooney, Jr. Formaldehyde and
paraformaldehyde study in funeral homes. Am. Ind. Hyg. Assoc.
J. 36:533-535, 1975.

124

103. Kerr, J. A., J. G. Calvert, and K. L. Demerjian. The mechanism
of photochemical smog formation. Chem. Britain 8:252-257, 1972.

104. Kitchens, J. E., R. E. Casner, G. S. Edwards, W. E. Harward III,
and B. J. Macri. Investigation of Selected Potential
Environmental Contaminants: Formaldehyde. U.S. Environmental
Protection Agency Report No. EPA-560/2-76-009. Washington,
D.C.: U.S. Environmental Protection Agency, Office of Toxic
Substances, 1976. 217 pp.

105. Klemm, R. B. , Absolute rate parameters for the reactions of
formaldehdye with 0-atoms and H-atoms over the temperature
range, .250-500K. J. Chem. Phys. 71:1987-1993, 1979.

106. Klemm, R. B. , E. G. Skolnik, and J. v. Michael. Absolute rate
parameters for the reaction of 0( P) with I^CO over the
temperature range 250 to 750 K. J. Chem. Phys. 72:1256-1264,
1980.

107. Kleopfer, R. D. Analysis of drinking water for organic

* compounds, pp. 399-416. In L. H. Keith, Ed. Identification and
Analysis of Organic Pollutants in Water. Ann Arbor, Mich.: Ann
Arbor Science Publishers, Inc., 1976.

108. Kopczynski, S. L., A. P. Altshuller, and F. D. Sutterfield.
Photochemical reactivities of aldehyde-nitrogen oxide systems .
Environ. Sci. Technol. 8:909-918, 1974.

109. Kuschner, M. , S. Laskin, R. T. Drew, V. Cappiello, and N.
Nelson. The inhalation carcinogenicity of alpha-halo ethers.
III. Lifetime and limited period inhalation studies with

b is (chloromethyl) ether at 0.1 ppm. Arch. Environ. Health 30:
73-77, 1975.

110. Laskin, S., R. T. Drew, V. Cappiello, M. Kuschner, and N.
Nelson. Inhalation carcinogenicity of alpha-halo ethers. II.
Chronic inhalation studies with chloromethyl methyl ether.
Arch. Environ. Health 30: 70-72, 1975.

111. Leggett, J. E., J. L. Sims, D. R. Gossett, U. R. Pal, and J. F.
Benner. Potassium and magnesium nutrition effects on yield and
chemical composition of Burley tobacco leaves and smoke. Can.
J. Plant Sci. 57:159-166, 1977.

112. Leighton, P. A. Photochemistry of Air Pollution. New York:
Academic Press, Inc., 1961. 300 pp.

113. Levy, H., II. Tropospheric budgets for methane, carbon monoxide,
and related species. J. Geophys. Res. 78:5325-5332, 1973.

114. Lin, C., R. N. Anaclerio, D. W. Anthon, L. Z. Fanning, and C. D.
Hollowell. Indoor/outdoor measurements of formaldehyde and
total aldehydes. Presented at American Chemical Society
Meeting, Washington, D.C., Sept. 9-14, 1979.

115. Lloyd, A. C. Tropospheric chemistry of aldehydes, pp. 27-48

^T'/*^' 1^' . and J - A ' Hod 9 es , Eds. Chemical
nf ! * * Mo * e:Lin * the Lower Troposphere. National
of Standards Special Publication 557. Washington, D.C. :
U.S. Government Printing Office, 1979.

A^h*' R '4 D ;/' Pierson ' S - T ' Brennan, C. W. Frank, and R.

Foam for P f ^ Associated wlth the e of Urea-Formaldehyde
Foam for Residential Insulation. Part I. The Effects of

125

Temperature and Humidity on Formaldehyde Release from
Urea-Formaldehyde Foam Insulation. Oak Ridge National
Laboratory Report ORNL/SUB-7 559/1. Washington, D.C.: U.S.
Government Printing Office, 1979. 89 pp.

117. Lovas, F. J., and R. D. Suenram. Identification of dioxirane

(H2COO) in ozone-olefin reactions via microwave spectroscopy.
Chem. Phys. Lett. 51:453-456, 1977.

118. Lovell, R. J. Emissions Control Options for the Synthetic
Organic Chemicals Manufacturing Industry: Formaldehyde Product
Report. EPA Contract No. 68-02-2577. Knoxville, Tenn.:
Hydroscience, Inc., for U.S. Environmental Protection Agency,
Office of Air Quality Planning and Standards, 1979. [150] pp.

119. Lyles, G. R. , F. B. Dowling, and V. J. Blanchard. Quantitative
determination of formaldehyde in the parts per hundred million
concentration level. J. Air Pollut. Control Assoc. 15:106-108,
1965.

120. MacCracken, M. C., and G. D. Sauter , Eds. Development of an Air
Pollution Model for the San Francisco Bay Area. Final Report to
the National Science Foundation. Vol. 2. Appendixes. Liverraore,
Calif.: Lawrence Livermore Laboratory, 1975. 948 pp. (abstract
in Energy Res. Abstr. 2:14714, 1977)

121. Mack, G. P. R. , and B. A. Thrush. Reaction of oxygen atoms with
carbonyl compounds. Part 1. Formaldehyde. J. Chem. Soc., Faraday
Trans. I 69:208-215, 1973.

122. Mack, G. P. R. , and B. A. Thrush. Reaction of oxygen atoms with
carbonyl compounds. Part 2. Acetaldehyde. J. Chem. Soc.,
Faraday Trans. I 70:178-186, 1974.

123. Major, R. T. The Ginkgo, the most ancient living tree. Science
157(3794) :1270-1273, 1967.

124. Martinez, R. I., R. E. Huie, and J. T. Herron. Mass
spectrometric detection of dioxirane, I^COO, and its
decomposition products, H 2 and CO, from the reaction of ozone
with ethylene. Chem. Phys. Lett. 51:457-459, 1977.

125. McKee, D. E., F. C. Ferris, and R. E. Goeboro. Unregulated
emissions from PROCO engine powered vehicles. SAE Report No.
780592. Warrendale, Pa.: Society of Automotive Engineers, Inc.,
1978. 23 pp.

126. McKinney, J. D., R. R. Maurer, J. R. Hass, and R. 0. Thomas.
Possible factors in the drinking water of laboratory animals
causing reproductive failure, pp. 417-432. In L. H. Keith, Ed.
Identification and Analysis of Organic Pollutants in Water. Ann
Arbor: Ann Arbor Science Publishers, Inc., 1976.

127. Mill, T. Structure Reactivity Correlations for Environmental
Reactions. U.S. Environmental Protection Agency Report No.
EPA-560/11-79-012. Menlo Park, Calif.: SRI International, for
U.S. Environmental Protection Agency, 1979. 66 pp.

128. Miller, B. H., and H. P. Blejer. Report of an Occupational
Health Study of Formaldehyde Concentrations at Maximes, 400 E.
Colorado Street, Pasadena, California. Study No. S-1838. Los
Angeles: State of California Health and Welfare Agency,

126

Department of Public Health, Bureau of Occupational Health,
1966. 5 pp.

129. Moortgat, G. K., and P. Warneck. CO and H2 quantum yields in
the photodecomposition of formaldehyde in air. J. Chem. Phys .
70:3639-3651, 1979.

130. Morris, E. D., Jr., and H. Niki. Mass spectrometric study of
the reaction of hydroxyl radical with formaldehyde. J. Chem.
Phys. 55:1991-1992, 1971.

131. Morris, E. D., Jr., and H. Niki. Reaction of the nitrate
radical with acetaldehyde and propylene. J. Phys. Chem.
78:1337-1338, 1974.

132. Morris, E. D., Jr., D. H. Stedman, and H. Niki. Mass
spectrometric study of the reactions of the hydroxyl radical
with ethylene, propylene, and acetaldehyde in a discharge-flow
system. J. Am. Chem. Soc. 93:3570-3572, 1971.

133. Morris, R. B., F. B. Higgins, Jr., J. A. Lee, R. Newirth, and J.
W. Pervier. Engineering and Cost Study of Air Pollution Control
for the Petrochemical Industry. Vol. 4. Formaldehyde Manufacture
with the Silver Catalyst Process. U.S. Environmental Protection
Agency Report No. EPA-450/3 73-006-d. Research Triangle Park,
N.C.: U.S. Environmental Protection Agency, Office of Air
Quality Planning and Standards, 1975. 94 pp.

134. Morris, R. B., F. B. Higgins, Jr., J. A. Lee, R. Newirth, and J.
W. Pervier. Engineering and Cost Study of Air Pollution Control
for the Petrochemical Industry. Vol. 5. Formaldehyde Manufacture
with Mixed Oxide Catalyst Process. U.S. Environmental
Protection Agency Report No. EPA-450/3-73-006-e. Research
Triangle Park, N.C.: U.S. Environmental Protection Agency,
Office of Air Quality Planning and Standards, 1975. 82 pp.

135. Moschandreas, D. J., J. W. C. Stark, J. E. McFadden, and S. S.
Morse. Indoor Air Pollution in the Residential Environment.
Vol. I. Data Collection, Analysis and Interpretation. U.S.
Environmental Protection Agency Report No. EPA-600/7-78-229a.
Research Triangle Park, N.C.: U.S. Environmental Protection
Agency, Office of Research and Development, Environmental
Monitoring and Support Laboratory, 1978. 201 pp.

136. National Research Council, Institute of Laboratory Animal
Resources. Laboratory Animal Housing. Proceedings of a
Symposium Held at Hunt Valley, Maryland, September 22-23, 1976,
p. 113. Washington, D.C.: National Academy of Sciences, 1978.

137. Natusch, D. F. S. Potentially carcinogenic species emitted to
the atmosphere by fossil-fueled power plants. Environ. Health
Persp. 22:79-90, 1978.

138. Niki, H., E. E. Daby, and B. Weinstock. Mass spectrometric
study of the kinetics and mechanism of the ethylene-atomic
oxygen reaction by the discharge flow technique at 300 K, p.
277. In 12th International Symposium on Combustion, Poitiers
France, July 14-20, 1968. Pittsburgh, Pa.: The Combustion
Institute, 1969.

127

139. Niki, H., E. E. Daby, and B. Weinstock. Mechanisms of smog
reactions. In Photochemical Smog and Ozone Reactions. Two
Symposia, 1971. Adv. Chem. Series 113:16-57, 1972.

140. Niki, H., P. D. Maker, C. M. Savage, and L. P. Breitenbach.
Fourier transform IR spectroscopic observation of pernitric aci
formed via HOO + N0 2 -* HOONO 2 . Chem. Phys. Lett. 45:
564-566, 1977.

141. Niki, H. , P. D. Maker, C. M. Savage, and L. P. Breitenbach.
Fourier transform IR spectroscopic observation of propylene
ozonide in the gas phase reaction of ozone-cis-2-butene-

f ormaldehyde . Chem. Phys. Lett. 46:327-330, 1977.

142. Niki, H., P. D. Maker, C. M. Savage, and L. P. Breitenbach.
Relative rate constants for the reaction of hydroxyl radical
with aldehydes. J. Phys. Chem. 82:132-134, 1978.

143. Ninomiya, J. S., and A. Golovoy. Effects of Air-Fuel Ratio on
Composition of Hydrocarbon Exhaust from Isooctane, Diiosbutyler
Toluene, and Toluene-n-Heptane Mixture. SAE Paper No. 690504.
New York: Society of Automotive Engineers, Inc., 1969. 11 pp.

144. Novak, J., J. "ziuticky, V. Kubelka, and J. Mostecky. Analysis
of organic constituents present in drinking water. J. Chromat.
76:45-50, 1973.

145. Osborne, A. D., J. N. Pitts, Jr., and E. F. Darley. On the
stability of acrolein towards photooxidation in the near
ultra-violet. Int. J. Air Water Pollut. 6:1-3, 1962.

146. Osborne, J. S., S. Adamek , and M. E. Hobbs . Some components oJ
gas phase of cigarette smoke. Anal. Chem. 28:211-215, 1956.

147. Osif, T. L., and J. Heicklen. Oxidation of HCO radicals. J.
Phys. Chem. 80:1526-1531, 1976.

148. Pefley, R. K., M. A. Saad, M. A. Sweeney, and J. D. Kilgroe.
Performance and emission characteristics using blends of
methanol and dissociated methanol as an automotive fuel. Papei
No. 719008, pp. 36-46. In Proceedings of the SAE Intersociety
Energy Conversion Engineers Conference, Boston, Mass., August
3-5, 1971. New York: Society of Automotive Engineers, Inc.

149. Pitts, J. N., Jr., A. M. Winer, K. R. Darnall, G. J. Doyle, an<
J. M. McAfee. Chemical Consequences of Air Quality Standards
and of Control Implementation Programs. Roles of Hydrocarbons
Oxides of Nitrogen and Aged Smog in the Production of
Photochemical Oxidant. Final Report to the California Air
Resources Board. Contract No. 4-214. Riverside: University o
California, Statewide Air Pollution Research Center, 1976.

444 pp.

150. Rasmussen, R. A. What do the hydrocarbons from trees contribut<
to air pollution? J. Air Pollut. Control Assoc. 22:537-543,
1972.

151. Renzetti, N. A., and R. J. Bryan. Atmospheric sampling for
aldehydes and eye irritation in Los Angeles smog 1960. J. Air
Pollut. Control. Assoc. 11:421-424, 427, 1961.

152. Santodonato, J., D. Basu, and P. Howard. Health Effects
Associated with Diesel Exhaust Emissions. Literature Review ai
Evaluation. U.S. Environmental Protection Agency Report No.

128

EPA-600/1-78-063. Research Triangle Park, N.C.: U.S.
Environmental Protection Agency, Health Effects Research
Laboratory, November 1978. 163 pp.

153. Schauenstein, E., H. Esterbauer, and H. Zollner. Aldehydes in
Biological Systems. Their Natural Occurrence and Biological
Activities, London: Pion Limited, 1977. 205 pp.

154. Schmidt, A., and H. Gotz. The formation of formaldehyde during
the burning of natural gas in household devices.
Gas-Wasserfach, Gas-Erdgas 118:112-115, 1977. (in German)

155. Schuck, E. A., E. R. Stephens, and J. T. Middle ton. Eye
irritation response at low concentrations of irritants. Arch.
Environ. Health 13:570-575, 1966.

156. Scott Research Laboratories, Inc. Atmospheric Reaction Studies
in the Los Angeles Basin. Phase I. Vol. II. pp. 143-149,
310-314. Washington, D.C.: U.S. Department of Health,
Education, and Welfare, Public Health Service, National Air
Pollution Control Administration, 1969.

157. Sellakumar, A. R. , R. E. Albert, G. M. Rusch, G. V. Katz, N.
Nelson, and M. Kuschner. Inhalation carcinogenicity of
formaldehyde and hydrogen chloride in rats. Abstract No. 424.
Proc. Am. Assoc. Cancer Res. 21:106, 1980.

158. Shackleford, W. M. , and L. H. Keith. Frequency of Organic
Compounds Identified in Water. U.S. Environmental Protection
Agency Report No. EPA-600/4-76-062. Athens, Georgia: U.S.
Environmental Protection Agency, Office of Research and
Development, Environmental Research Laboratory, 1976. 626 pp.

159. Sheldrick, J. E., and T. R. Steadman. Product/Industry Profile
and Related Analysis on Formaldehyde and Formaldehyde-Containing
Consumer Products. Part II. Products/industry Profile on Urea
Formaldehyde. Columbus, Ohio: Batttelle Columbus Division, for
U.S. Consumer Product Safety Commission, 1979. [24] pp.

160. Sheldrick, J. E., and T. R. Steadman. Product/Industry Profile
and Related Analysis on Formaldehyde and Formaldehyde-Containing
Consumer Products. Part III. Consumer Products Containing
Formaldehyde. Columbus, Ohio: Battelle Columbus Division, for
U.S. Consumer Product Safety Commission, 1979. [39] pp.

161. Shipkovitz, H. D. Formaldehyde Vapor Emissions in the
Permanent-Press Fabrics Industry. Report No. TR-52.
Cincinnati: U.S. Department of Health, Education, and Welfare,
Public Health Service, Consumer Protection and Environmental
Health Service, Environmental Control Administration, 1968. 18
pp.

162. Singleton, D. L., R. S. Irwin, and R. J. Cvetanovic. Arrhenius
parameters for the reactions of 0( 3 P) atoms with several
aldehydes and the trend in aldehydic C-H bond dissociation
energies. Can. J. Chem. 55:3321-3327, 1977.

163. Smith, C. R. , and E. H. Spaulding. Myobactericidal agents, p.
1039. In L. S. Goodman and A. Oilman, Eds. Pharmacological
Basis of Therapeutics. 4th ed. New York: Macmillan Publishing
Co., Inc., 1970.

129

1.64. Smith, C. W. , Ed. Acrolein. New York: John Wiley & Sons, Inc.,
1962. 273 pp.

165. Smith, R. H. Rate constants and activation energy for the
gaseous reaction between hydroxyl and formaldehyde. Int. J.
Chem. Kinet. 10:519-527, 1978.

166. Springer, K. J., and R. C. Stahman. Diesel Car

Emissions Emphasis on Particulate and Sulfate. SAE Paper No.
770254. Warrendale, Pa.: Society of Automotive Engineers, Inc.,
1977. 32 pp.

167. SRI International. Class Study Report. Aldehydes. Menlo Park,
Calif.: SRI International, for National Cancer Institute,
Chemical Selection Working Group, 1978. 19 pp. + data package.

168. Stahl, Q. R. Preliminary Air Pollution Survey of Aldehydes. A
Literature Review. National Air Pollution Control
Administration Publication No. APTD 69-24. Raleigh, N.C.: U.S.
Department of Health, Education, and Welfare, Public Health
Service, National Air Pollution Control Administration, 1969.

169. Stief, L. J., D. F. Nava, W. A. Payne, and J. V. Michael. Rate
constant for the reaction of hydroxyl radical with formaldehyde
over the temperature range 228-362 K, pp. 479-481. In
Proceedings of the NATO Advanced Study Institute on Atmospheric
Ozone: Its Variation and Human Influences. Washington, D.C.:
U.S. Department of Transportation, Federal Aviation
Administration, 1980.

170. Su, F., J. G. Calvert, and J. H. Shaw. An FT IR spectroscopic
study of the ozone-ethene reaction mechanism in O2~rich
mixtures. J. Phys. Chem. 84:239-246, 1980.

171. Su, F. , J. G. Calvert, and J. H. Shaw. The Mechanism of the
photooxidation of gaseous formaldehyde. J. Phys. Chem. 83:
3185-3190, 1979.

172. Su, F., J. G. Calvert, J. H. Shaw, H. Niki, p. D. Maker, C. M.
Savage, and L. D. Breitenbach. Spectroscopic and kinetic
studies of a new metastable species in the photooxidation of
gaseous formaldehyde. Chem. Phys. Lett. 65:221-225, 1979.

173. Suta, B. E. Population Exposures to Atmospheric Formaldehyde
inside Residences. CRESS Report No. 113. Menlo Park, Calif.:
SRI International, for U.S. Environmental Protection Agency,
Office of Research and Development, 1980. [78] pp.

174. Suta, B. E. Production and Use of 13 Aldehyde Compounds. Menl<
Park, California: SRI International, for U.S. Environmental
Protection Agency, Office of Research and Development, 1979.
[32] pp.

175. Tabershaw, I.R., H.N. Doyle, L. Gaudette, S. H. Lamm, and 0.
Wong. A Review of the Formaldehyde Problems in Mobile Homes.
Rockville, Maryland: Tabershaw Occupational Medical Associates,
P. A., for National Particleboard Institute, 1979. 19 pp.

176. Tija, B. and T. J. Sheehan. Effect of urea formaldehyde slow
release fertilizers on growth and leaf pigmentation of Euphorbi.
pulcherrima Willd. HortScience 12:383, 1977. (abstract)

177. Tomas, M. Liberation of formaldehyde during the hardening of
urea-formaldehyde resins at high temperatures. Holztechnot.

130

5:89-91, 1964. (in German; English abstract in Abstr. Bull.
Inst. Paper Chem. 35:1118, 1965)

178. Tuazon, E. C., R. A. Graham, A. M. Winer, R. R. Easton, J. N.
Pitts, Jr., and P. L. Hanst. A kilometer pathlength
Fourier-transform infrared system for the study of trace
pollutants in ambient and synthetic atmospheres. Atm. Environ.
12:865-875, 1978.

179. Tuazon, E. C., A. M. Winer, R. A. Graham, and J. N. Pitts, Jr.
Application of a kilometer pathlength FT-IR spectrometer to
analysis of trace pollutants in ambient and simulated
atmospheres, pp. 798-802. In Proceedings of the 4th Joint
Conference on Sensing Environmental Pollutants, 1977.
Washington, D.C.: American Chemical Society, 1978.

180. U.S. Department of Health, Education, and Welfare, National Air
Pollution Control Administration. Air Quality Criteria for
Hydrocarbons. DHEW Publication No. AP-64. Washington, D.C.:
U.S. Government Printing Office, 1970. 118 pp.

181. U.S. Department of Health, Education, and Welfare, Public Health
Service, Health Services and Mental Health Administration. The
Health Consequences of Smoking. A Report of the Surgeon
General: 1972. DHEW Publication No. (HSM) 72-7516 . Washington,
D.C.: U.S. Government Printing Office, 1972. 158 pp.

182. U.S. Department of Labor, Occupational Safety and Health
Administration. Table Z-2, p. 594. In Occupational safety and
health standards. Subpart Z. Toxic and hazardous substances. 29
CFR 1901.1000, July 1, 1980.

183. U.S. Environmental Protection Agency, Office of Toxic
Substances. Preliminary Assessment of Suspected Carcinogens in
Drinking Water. Interim Report to Congress. Report No. EPA
560/4-75/003. Washington, D.C.: U.S. Environmental Protection
Agency, 1975. 39 pp.

184. U.S. Environmental Protection Agency, Region VI. Analytical
Report: New Orleans Area Water Supply Study. Report No. EPA
906/9-75-003. Dallas: U.S. Environmental Protection Agency,
1975. 90 pp. J

185. united States of America Standards Institute. USA Standard.
Acceptable Concentrations of Formaldehyde. New York: United
States of America Standards Institute, 1967. 8 pp.

L86. Waddington, D. V., E. L. Moberg, J. M. Duich, and T. L.

Watschke. Long-term evaluation of slow-release nitrogen sources
7 Sr 11 ,!" rfgrass - Soil Sci - s c. Am. J. 40:593-597, 1976.

Mn n^n' ^ !' / ormaldeh y de - American Chemical Society Monograph
No. 120. 2nd ed. New York: Reinhold Publishing Corp., 1953.

3 / 3 PP

88 '

ambient air. Science 189:797-800,

i, . --. J. Satish, M. Meier, and H. Sommer
pollution in the vicinity of streets, pp. bo er.

Amsterdam: Elsevier, 1976.

131

190. Weber -Tschopp, A., T. Fischer, and E. Grandjean. Irritating
effects of formaldehyde on men. Int. Arch. Occup. Environ.
Health 39:207-218, 1977. (in German)

191. Wigg, E. E. Reactive Exhaust Emissions from Current and Futu
Emission Control Systems. SAE Paper No. 730196. New York:
Society of Automotive Engineers, Inc., 1973. 21 pp.

192. Wigg, E. E. , R. J. Campion, and W. L. Petersen. The Effect o
Fuel Hydrocarbon Composition on Exhaust Hydrocarbon and
Oxygenate Emissions. SAE Paper No. 72051. New York: Society
Automotive Engineers, Inc., 1972. 17 pp.

193. Wild, H. The liberation of formaldehyde during the hardening
urea-formaldehyde resins. Holztechnot. 5:92-95, 1964. (in
German; English abstract in Abstr. Bull. Inst. Paper Chem. 35
1120-1121, 1965)

194. Williams, J. E., and H. S. Siegel. Formaldehyde levels on an
in chicken eggs following preincubation fumigation. Poultry
Sci. 48:552-558, 1969.

195. Wilson, W. E. f Jr., A. Levy, and E. H. McDonald. Role of SC>2
and photochemical aerosol in eye irritation from photochemica
smog. Environ. Sci. Technol. 6:423-427, 1972.

196. World Health Organization Working Group. Health Aspects Rela
to Indoor Air Quality. Copenhagen, Denmark: World Health
Organization, 1979. 34 pp.

197. Zafiriou, 0. C., J. Alford, M. Herrera, E. T. Peltzer, R. B.
Gagosian, and S. C. Liu. Formaldehyde in remote marine air ai
rain: flux measurements and estimates. Geophys. Res. Lett. 7
341-344, 1980.

CHAPTER 6
ANALYTICAL METHODS FOR THE DETERMINATION OF ALDEHYDES

Air-quality standards and pollution-control legislation are
generally based on the assumption that exceeding some concentration of
any given pollutant will have harmful effects on human health that
outweigh any economic disadvantage of imposing regulatory standards.
Accurate determination of such "threshold concentrations" demands
accurate methods of analysis.

This chapter discusses analytical methods currently used for
aldehydes, including techniques of sampling and calibration, and other
available or potentially available methods. In general, the
analytical methods for aldehydes are difficult, and much developmental
work is needed. Where possible, estimates of the accuracy, precision,
and applicability of the various measurement methods are presented.
An assessment of the state of the art is given in Chapter 2, and some
recommendations for future action are presented in Chapter 3.

METHODS OF GENERATING STANDARDS

All methods of analysis have in common the need for calibration.
Calibration is performed by applying the chosen method of analysis to
a standard. The standard can be prepared by weighing (a primary
standard) or measured by an independent primary reference method of
analysis (a secondary standard). In the case of aldehydes, the
standard is usually a liquid solution or a gas-phase mixture of one or
more aldehydes. Liquid solutions are static; gas-phase mixtures can
be static or dynamic (i.e., generated continuously). This section
discusses the preparation of standards and their application to
calibration.

STATIC METHODS

Aqueous solutions of aldehydes can be used as standards for
calibration. The solutions are usually obtained by dissolving an
appropriate amount of the desired aldehyde in water. Ordinary
reagent-grade aldehydes are often used without purification, although
for accurate work it is imperative to distill the aldehyde before use,
because oxidation and polymerization occur on standing.

132

133

Primary standardization can be achieved by straightforward
application of gravimetric or volumetric methods. It is also possifc
to prepare a secondary-standard solution of aldehyde by oxidative
titration. Two methods described by Walker 142 are suited to the
analysis of aldehydes other than formaldehyde: the alkaline peroxid
and iodometric methods, which rely on the oxidation of an aldehyde t
its corresponding carboxylic acid. Once oxidized, the acidic soluti
can be titrated. These reactions are characteristic of all aldehyde
so there should be no problems in applying the methods to the
preparation of a secondary-standard solution of any (pure) aldehyde.

It is difficult to prepare a primary-standard solution of
formaldehyde, because pure formaldehyde is not readily available.
There are, however, two ways to prepare formaldehyde solutions for
standardization by a primary reference method. The easier (but less
desirable) is to dilute commercial formalin (37% formaldehyde w/w) t
the approximate desired concentration. Unfortunately, solutions so
obtained will contain methanol, which is added to formalin as a
stabilizer, as an impurity. A methanol-free formaldehyde solution c.
be obtained by refluxing an appropriate amount of pure
par a formaldehyde in water and filtering the resulting solution.

For standardizing formaldehyde solutions prepared by these
methods, Walker 11 * 2 described several methods. A simple and accurate
primary reference method involves the addition of an aliquot of
formaldehyde solution to a neutral solution of sodium sulfite to for
a bisulfite addition product and sodium hydroxide. The hydroxide
released can be neutralized with a primary acid standard to
standardize the solution. The neutralization can be monitored with ,
pH meter.

A second method is the bisulf ite-iodine titration procedure. 10 l
Excess sodium bisulfite is added to the formaldehyde solution to fori
a bisulf ite-formaldehyde adduct at neutral pH. The unreacted
bisulfite is then destroyed with iodine. Addition of a carbonate
buffer releases the bisulfite from the bisulf ite-formaldehyde adduct
and the freed bisulfite is titrated with iodine (starch is used an ai
indicator). The iodine solution itself must be standardized with
sodium thiosulfate. Furthermore, one may encounter problems
associated with the stability of the iodine reagent. In summary, th<
method is complex and has several sources of possible error.

Standardization methods based on bisulfite are recommended for us
only with formaldehyde, because the formation of the
bisulfite-aldehyde adduct with other aldehydes may be less than
quantitative. llt2

DYNAMIC METHODS

Aldehydes are reactive compounds, so it is difficult to make
calibration gases that are stable for any useful period. This
precludes the use of gas-tank standards, unless the concentration of
aldehyde is very high (several percent) . Recent advances in render ir
gas-tank surfaces inert may alter this situation, but no data are

134

available. For most applications, it is currently necessary to use
dynamic methods to generate gas-phase-aldehyde standards.

Permeation tubes have been used to generate dynamic gas standards
for many different types of compounds and can be used for aldehydes as
well. These tubes contain pure compound in a length of Teflon tubing
capped at both ends. Over time, material diffuses through the Teflon
wall at a low and constant rate, provided that the temperature is held
constant. 119 Tubes for acetaldehyde, propionaldehyde, and
benzaldehyde are commercially available, and tubes could undoubtedly
be constructed for other aldehydes. These tubes are calibrated
gravimetrically (and are thus classified as primary reference
standards) and can be used with a constant-flow system to generate
primary gas standards in the concentration range of parts per billion
to parts per million.

Permeation tubes containing pure formaldehyde do not exist. The
vapor pressure of pure formaldehyde would be too high to permit the
construction of permeation tubes, if it were not already prone to
polymerization at room temperature. Construction of a permeation tube
for formaldehyde has been attempted with paraformaldehyde. At 80 C,
the decomposition rate of the polymer is great enough that a usable
permeation rate can be obtained. However, the gas in equilibrium with
paraformaldehyde is not pure formaldehyde; it contains substantial
amounts of methylal, methyl formate, orthoformate, and water. l< * 2
Thus, co-emission of these gases with formaldehyde from the
paraformaldehyde permeation tube may make gravimetric calibration
impossible.

One of the simplest methods for generating a gaseous aldehyde is
to use the headspace vapor of an aqueous solution of the aldehyde.
This method has been used to generate acrolein for use in assessing
molecular sieves as aldehyde adsorbents. 1 * 8 The method is especially
applicable to the generation of gaseous formaldehyde standards. It
must be noted that, because formaldehyde is almost entirely hydrated
to methylene glycol, CH2(OH) 2 , in aqueous solution, it has a much
lower vapor pressure than would otherwise be expected. The apparent
Henry's law constant (2.77 torr/mol-fraction) for formaldehyde was
determined in 1925 by Ledbury and Blair. 76

Use of aqueous headspace vapor does not provide a primary standard
lirectly. The gas must be standardized in a secondary manner usually
>y measuring the amount of aldehyde lost from the solution. It is
>ossible to assess the efficiency of a collection device by comparing
.he amount lost from a source solution with the amount of aldehyde
rapped .

A second, related method for generating gas-phase aldehyde
tandards involves the slow addition of a dilute aqueous solution of
n aldehyde to a gas stream in such a way that the aldehyde solution
vaporates entirely. By knowing the rate at which the aldehyde is
eing added to the gas stream and the flow rate of the dilution gas,
ne can determine the aldehyde concentration in the gas stream. A
evice implementing this method was constructed with a syringe pump to
nject the aldehyde solutions into a heated section of tubing through
hich the dilution gas was flowing. 77 * The purity of the gas

135

standards generated by this method depends on the purity of the liq
solutions. In the case of formaldehyde, again/ it is desirable to
methanol-free formaldehyde solutions. Gases made this way will cont
a great deal of water (as occurs with the headspace technique) , whi
is undesirable in some cases. There may also be some decomposition
aldehyde. 77 As a secondary reference method, the technique must be
used with caution.

A promising, although relatively unused, technique that has bee
used to generate low concentrations of aldehydes involves the therm
or catalytic decomposition of precursor compounds. In one study,
formaldehyde was generated through the decomposition of a gas strea
of ^-trioxane (the cyclic trimer of formaldehyde) as it passed over
phosphoric acid-coated substrate (A. Gold, personal communication) .
In a second study, olefinic alcohols were thermally decomposed into
mixture of an aldehyde and an olefin (e.g., 3-methyl-3-butene-l-ol
gives formaldehyde, 4-pentene-2-ol gives acetaldehyde, and 5-methyl
l,5-hexadiene-3-ol gives acrolein) . The olefinic alcohol was
introduced into the gas phase with a diffusion or permeation tube ai
is decomposed in a heated gold tube. Decomposition of the parent
olefinic alcohol is virtually quantitative, so the technique general
a primary standard. It is also possible to use gas chroma tog raphy c
a secondary reference method to analyze for the olefin produced in 1
reaction. When this method is used to generate standards for gas-
chromatographic analytic techniques, the olefin can be used as an
internal standard. One advantage of this method is that undesirable
compounds are never handled in bulk, inasmuch as they are generated
only in small amounts as they are used. This method has been used t
generate standards of formaldehyde, acetaldehyde, and acrolein as Ic
as a few parts per million. 136 Other thermal decompositions of
precursor compounds have been used to obtain vinyl chloride and
acrylonitrile. <t3

SAMPLING

An essential aspect of any analytic technique is the method of
sampling. Choice of a method of sampling must be consistent with th
information desired. Techniques that take an integrated sample over
long period can concentrate pollutants and simplify analysis. Such
techniques are applicable when the determination of mean exposure is
desired. Techniques that provide real-time measurements usually
require sophisticated equipment, but may be required when it is
desirable to observe concentration fluctuation during a short period
In the monitoring of compliance of pollutant concentrations with
specific values set by a government agency, high precision is needed
in the study of trends, it is more important to have a reproducible
method.

136

IR

In the analysis of air pollutants, both direct and indirect
ampling methods may be used. The direct method uses such instruments
s infrared and microwave spectrophotometers, which are capable of
easuring the concentrations of compounds in situ. Direct sampling
echniques and direct investigative methods are discussed later in
his chapter. When the compounds of interest are present in extremely
ow concentrations, thus precluding direct measurement, or when
ampling sites are inaccessible to sophisticated instruments, indirect
ampling techniques are commonly used.

Indirect sampling can consist merely of taking a representative
rab sample. Air to be sampled is admitted into a previously
vacuated vessel or pumped into a deflated bag. Inert materials such
s Teflon, Tedlar, and stainless steel are used to construct
rab-sampling containers. The sample is returned to a central
aboratory and analyzed as though the measurement were being made in
itu.

Grab sampling suffers from two defects. Because no
reconcentration has been effected, the laboratory measurement
echnique must be sensitive enough to determine ambient concentrations
irectly. A more serious problem arises from the relatively long time
hat the low concentrations of the pollutants to be measured are in
ontact with the high surface area of the grab-sampling container,
onspecific site adsorption occurs often, and a substantial fraction
f the sample is lost. The container may develop a "memory 11 and give
ise to spuriously high determinations on successive samples. Careful
alibration and scrupulous analytic technique may minimize this latter
efect. 31 98 122 1! 6

reconcentration Sampling with Subsequent Analysis

A common indirect sampling technique involves preconcentrating the
ample at the sampling site, e.g., by passing air through an absorbing
Lquid. There are two advantages. Preconcentration makes analysis in
laboratory easier, inasmuch as a higher detectability limit can be
Dlerated. And preconcentration often stabilizes the sample. In
arapling for aldehydes, preconcentration techniques are almost always
5ed.

As noted previously, preconcentration devices are generally used
i sampling aldehydes in ambient air. Impingers are used most often
:>r trapping low-molecular-weight aldehydes. Many types of impingers

accommodate Different sampling applications

If the collection efficiency of the trapping solution is less than
10%, it is desirable to use more than one impinger in series. A
Apical arrangement for the sampling of formaldehyde (as recommended
' NIOSH) us consists of two midget impingers in series, each
xitaining 10 ml of water. The sample is collected at a flow rate of 1

137

1I

a

L.J

D

a. Midget Impinger.
Ace Glass Co.

b. Midget Gas Bubbler
(coarse frit) .
Ace Glass Co.

c. Nitrogen Dioxide Gas Bub
Ace Glass Co.

J*-

m

1
i

Spiral Type Absorber.

American Society for Testing Materials.
Tentative Methods of Sampling Atmos-
pheres for Analysis of Gases and Vapors,
Philadelphia, PA, July 24, 1956.

Packed Glass -Bead Column.
American Society for Testing Material!
Tentative Methods of Sampling Atmos-
pheres for Analysis of Gases and Vapo]
Philadelphia, PA, July 24, 1956.

f. Midget Impinger

Lawrence Berkeley Laboratory.

Bubbler Absorber with D iff user.
American Society for Testing Materials
Tentative Methods of Sampling Atmos-
pheres for Analysis of Gases and Vapors
Philadelphia, PA, July 24, 1956.

FIGURE 6-1 Various types of impingers used to sample air. a-e and g
reprinted with permission from Pagnotto; 98 f from C. D. Hollowell
(personal communication).

138

standard liter per minute (slpm) . The final solution is analyzed
color imetrically.

It is desirable to use an ice bath or a refrigerated sampler with
impingers. Otherwise, low relative humidity or high ambient
temperature may cause the impinger solution to evaporate, thus
limiting the sampling time. The solubility and stability of the
aldehyde in the trapping solution may also be adversely affected if
impingers are not kept cold.

Figure 6-2 shows two designs for aldehyde samplers used by R.R.
Miksch e_t al. (unpublished manuscript) . The impinger sampling trains
are contained in a small refrigerator. One sampler has a separate
flow-control system that can sample air at a constant mass flow rate
even when the pressure drop across the sampling train varies. The
second sampler uses a critical orifice for flow control.

The absorbing solution used in the impinger depends on the
aldehyde to be analyzed. In many cases, the solution contains a
trapping reagent that is a constituent of the analytical procedure,
thus simplifying operations. In general, there are two categories of
trapping solutions for aldehydes. The first "category" is simply
water. Formaldehyde reacts rapidly with water to form the relatively
nonvolatile hydrate, methylene glycol. Methylene glycol does have a
finite vapor pressure, however, and saturation may occur if sampling
times are excessively long. This problem can be minimized by using two
impingers in series. The collection efficiency of a single impinger
containing water will decrease with time, but two impingers in series
will maintain a collection efficiency of over than 95% for sampling
times of over 48 h (Miksch ^t all. , unpublished manuscript).

Water does not appear to be an especially good reagent for
trapping higher-molecular-weight aldehydes, because the equilibria do
not favor the formation of the hydrates. 16 To use aqueous bubblers
to trap higher-molecular-weight aldehydes, an additional carbonyl
scavenger must be present in the trapping solution. Carbonyl
scavenger compounds constitute the second category of aldehyde-
trapping solutions. The scavengers are chosen for their ability to
react rapidly and quantitatively with carbonyl-containing compounds to
form nonvolatile adducts. The reagents selected have included
bisulfite, hydroxylamine , semicarbazone , and several phenylhydrazines,
all of which have been shown to react extremely rapidly with
aldehydes. 17 Table 6-1 shows the collection efficiency for
different aldehydes of various trapping solutions that contain
scavengers. The data are compiled from a number of sources and not
always consistent, owing to the different experimental conditions
used. The choice of a carbonyl-scavenger trapping agent depends on
the analytical method to be used.

Higher-molecular-weight aldehydes also have been detected by means
of solid adsorbents. The most widely used solid adsorbent is the
porous polymer Tenax-GC, which has been used extensively to measure
atmospheric organic compounds, including aldehydes, at low
concentrations. In practice, the procedure is best suited for
organics in the range Cg to Ci2- Pellizzari * 3 10H has reported
e inding several aldehydes in ambient air with this method.

cu
sd

oo

CO43 CTi
CO

I s - rH -O CM

r* ro m ^r

CO

CQ O O O O O

01 S 3 3 53 3

42
cu

O

4-)

CO

a
o

H

4J

H
O

ff

H
Cu
CL,

cd

J-i
H

CO

O
H
M
cd

4-1
o

co
cu

H

o

C
CU

4-1
w

a
o

H
4J
O

a)

H
H

o
o

o

H
-M

cdca
M

TJ

cd cu
o a

fl >.

o o

H a

4_l 0)

O H

cu o

rH -H

rH 4-1

O 4-1

O ft]

0)

3

PI
O
H
4J

d

ff

<tJQ'ij

O- -O O
00 SO X>

cs oo
ON oo

CM

CTi

<u

X)

-8

CU 43

TJ a>

>^ T3

H O

Co *rH

^J OH

cu o

O M

< CM

a

d

cfl

s

pq
I ,

1

cd
cu

l\

43
CU

o cd

ij ri

o C

c
o o

^Q 'H

u cu

CM O

|r| ^
O f^

N
N CCj
fl M
CU T3

42 >>

1 43
<N

>
43
4J
il

S

43
CU

H CO

cd T3
cu
o -u TJ

H cd -H
ft H O

o w cd
M a
w cu a

o o

o

139

43 d
CU O

cdcd

H T3

43 O

H 43

iH U

Cd CU

U 33

d ^ '

B ? I

ss

4J (\)

O -H '
CU O

r-l 4-1
O 4-1
U W 5s?

continued

I

^O

43

$

o

A

s,
1

3O

o

CTi

i i

X) r-

i
3

d
o

H
4J

T-H

CO

ted Formaldehyde
c acid

CU

cu

d

H

enylhydrazine Mixed

CU

X

Acrolein

.nd 4-hexyl- Acrolein
nol

cd iH

CD

43

CO H

apping

ncentr
sulfur

H

|

CX/*-N
o ad

P 53

H a
d s - /

H
M

cd

M

H

43

hanol
resorc

J_l

o

^

H

H

-P

4J

H

a

a

O

M

4-1 O
O CO

cd cu

J-l T3
O H

ex co
cd

> n

CU CU

ex o

ex o
i a
cu cd

H CU

co ex

CO

cq cd
0)

o

u cu

CO

O 3

4-1

M a"

CU

efd

H O

ex -H

4J

ed LJ

3 3

rH

ex

H

P

o

CO CO

CO

M

3

H CU

d

4-1 43

8

CU

-o

-d

cu

s -a

43
CO

4_>

H

Cd 4H

H

M

43

3

> d

ex

4J

.. cd

CO t-t

T)

o PX

43 Cd

4J >

CU CU

d U

o d

H 5

u d o

cd o d

M -H J^

43 -P d

H 3 3
H iH

cd O -

O co W

cd

cd|

43
O
CO

140

141

Sampler With Separate Flow Control

fS AMP LING
ITRAIN 1

Impingers

Solenoid
valves

L

_i

r~ ^ R2

i cft^

*-7*- rump ,

I GO^Z

I Rl .1 A

-iv2

I vu v PF

I 60- PR

- prefil:er

1 \cy ' rn

1 rn PR V1 - V2

-|_ir i _R1.R2

' -r- J " G

- valves
- roiometers
- vacuum guage

1 ElpBPF ^VR

j . o 2 ^^

- vacuum regulator

24 hr repeat

1 '. J

timer

_1 I

Sampler With Self - Contained Flow Control

|SAMP!TN(F
TRAIN 1

Pump

y <->

. " h I Vacuum
^>^^ ^v | guage

Impingers ] j
Critical orifice |

^ 9 . L

| I

Elapsed timel |
indicator | j

I
24 hr repeat I \ I

^3 2 ^ |
-^4 ,

timer | |
J

FIGURE 6-2 Sampling systems for sequential sampling of formaldehyde/
aldehydes. Reprinted with permission from R. R. Miksch.

142

Other solid adsorbents also have been used. Molecular sieves have
been used to capture low-molecular-weight aldehydes by physical
entrapment. Samples can be desorbed with water for analysis by
gas-chromatographic or colorimetric techniques. Formaldehyde,
acetaldehyde, and acrolein have all been detected with molecular
sieves, but quantitative data are available only on acrolein. ** 8 The
solid adsorbents, charcoal and silica gel, also have been
investigated, but the results have not been promising. It has been
difficult to effect quantitative desorption of collected aldehydes.

It should be noted that a standard source of aldehyde gas is not
required to estimate the collection efficiency of a given sampling
device. Several devices can be placed in series and the fraction of
the total sample collected in each device determined. This technique
has been used to obtain collection efficiencies, 8 31 but the
method is not necessarily reliable. It can be determined that a
sampling device is unsatisfactory; in that event, the sample will be
distributed throughout the system. However, the observation that no
sample has gotten past the first trap does not guarantee that the
collection has been quantitative, inasmuch as the sample may have
decomposed or have been otherwise lost. The only reliable means for
determining the collection efficiency of a sampling device is the use
of a gas standard.

A sampling device of recent development that has not been applied
to aldehydes is the passive monitor. The monitor consists of a
diffusion tube containing a trapping agent at one end. The device is
inexpensive and easy to use, expediting large-scale sampling. Palmes
e_t al. " have been instrumental in developing the theory of passive
monitors and successfully constructing a passive monitor for nitrogen
dioxide.

Continuous Samplers

As stated earlier, there are direct investigative methods for
determining the concentrations of compounds in situ, e.g., infrared
and microwave spectroscopy. None of these methods has been rendered
sufficiently portable to be used in field studies. The details of
these methods and their potential future applications are discussed
later in this chapter.

Several continuous analyzers based on wet chemical methods have
been constructed. 27 fll * iso These analyzers are intended to combine
the best elements of direct and indirect sampling. Air is sampled via
an impinger apparatus to generate a preconcentrated sample that,
instead of being transported to a central laboratory for analysis, is
analyzed in the field.

The continuous analyzer described by Yunghans and Munroe 150 and
Cantor 27 is manufactured by Combustion Engineering Associates
(CEA) . The instrument can use the pararosaniline method to analyze
for formaldehyde, or it can use the Purpald method to measure total
aldehydes. One problem with this instrument is that it is not
thermostated. The color -development rate of pararosaniline is

143

temperature-sensitive (Lahmann and Jander 7 3 and Miksch et al. ,
unpublished manuscript), and this may lead to erratic results. The
impinger absorber coil is also sensitive to temperature fluctuations,
because the collection efficiency of the absorbing solution and the
amount that evaporates into the air stream depend on temperature. The
mercury reagents used with the pararosaniline procedure are toxic.
Finally, the recommended color-development time is too short to allow
full color development that ensures maximal sensitivity and stability.

WATER

Sampling of water for analysis of aldehydes entails obtaining one
or more representative grab samples. Because industrial effluents and
water from natural bodies of water are not homogeneous, some
investigators prefer to collect several subsamples and combine them
for analysis. These subsamples are usually collected at various times
and from different locations.

The preferred sample container is a glass jar with a Teflon-lined
cap. Both jar and cap should be thoroughly cleaned with detergent anc
water and rinsed well with distilled water and, if an organic solvent
is used for extraction, with the organic solvent. The volume of
sample collected depends on the desired detection. Usually 1-2 L is
sufficient if the desired detection exceeds 2 ppb, and the GC/MS
technique is used after proper sample extraction and concentration.

If the time between collection and analysis is expected to be
fairly long, the samples should be stored at 4C or, preferably, kept
frozen, to prevent biologic or chemical degradation of the aldehydes.

PLANT MATERIAL

A literature review of the last two decades reveals many
variations in the preparation of samples, methods of extraction, and
analytic techniques for measuring aldehydes in plant tissue.

Sample preparation has involved several procedures. Free-run juic
of apple and grape have been concentrated 100 times and used for
analysis. 1 * 1 132 Tomato fruit has been cored, quartered, and reduced
to a slurry in a stainless-steel sampler before analysis. 107 Winter
and Sundt 11 * 7 crushed plant tissue under nitrogen because of their
evidence that 2-hexenal content of plant tissue varies with the oxyge
concentration in the atmosphere at the time of crushing. Teranishi e
aj.. 135 avoided crushing and processing and sampled aromas from fresh
fruit directly.

Extraction of aldehydes from plant products has been accomplished
either with solvents or with distillation. Purified isopentane has
been used to extract aldehydes from apple and fruit juices; after the
extract is dried, it is washed with propylene glycol to remove
alcohols; the remaining oil is ready for aldehyde analysis. 132
Alternatively, steam distillation has been used to recover aldehydes:
Major et^a]^. 85 steam-distilled fresh Ginkgo biloba leaves, collected

144

the distillate, and extracted it with ether. Tomato was similarly
distilled and extracted with diethyl ether and dried over anhydrous
sodium sulfate. Winter distilled strawberry fruit under nitrogen to
avoid the oxidation of unsaturated fatty acids that are the precursors
of aldehydes.

WET-CHEMISTRY SPECTROPHOTOMETRIC ANALYSIS

Wet-chemistry spectrophotometric methods of analysis for aldehydes
continue to be the most popular and widely used. The sensitivity
associated with the formation of a dye chromophore and the ease of
measurement with readily available spectrophotometers are not easily
matched by other techniques. Field samples can usually be easily
generated with simple equipment. However, spectrophotometric
techniques are subject to error. The specificity and degree of
completion of the chroraophore-forming reaction must be considered, as
well as the stability and standardization of reagents. In many cases,
spectrophotometric techniques are slower than more direct measurement
methods.

To sample air, wet-chemistry spectrophotometric methods are often
applied to preconcentrated samples that are generated with impingers.
It is often overlooked that the detection limit for aldehydes in air
depends on both the sensitivity of the analytical method and the
degree of preconcentration . If the time or flow rate is changed in
sampling with impingers, the detection limit can be changed
radically. Typically, aldehydes in air are sampled for 0.5-8 h at
flow rates of 0.5-2.0 L/min.

FORMALDEHYDE

To date, only spectrophotometric techniques have been applied in
field studies of formaldehyde. Table 6-2 lists a variety of spectro-
photometric techniques that can be used to analyze formaldehyde. The
most widely used methods have been based on chromotropic acid, as
tentatively recommended both in NIOSH 139 and in American Public
Health Association Intersociety Committee. 10 Pararosaniline has
been the next most popular reagent and may have some advantages over
chromotropic acid. The remaining reagents have not been widely used.
Some are inappropriate for field sampling, and others have not been
adequately tested.

Chromotropic Acid

Ever since Eegriwe 97 described the use of chromotropic acid in a
spot-test method for the detection of formaldehyde, there has been
widespread interest in using this reagent for spectrophotometric
determination of formaldehyde. As stated above, a tentative method
using this reagent has been suggested by both NIOSH 139 and the

OJ

in Ambient Air

Reference

ide, alkenes, 8,139
taldehyde, phenol,

precursors

30

0)

o

H

(3

cd

r*l O
O -H
4-1
> H
0) U

m

rH
00

oo
cu

rH

43

vO

rH

-H
CO

I-l

CO

U
0)
I-l

precursors 116

e, aliphatic 12

o
o

H
MH
H
O

tic aldehydes 117

CSI
CO

i

rH

ing a difference of 0.05 absorben

CO

CO

X 0)

TJ CU

cd

-o

0)

cd

*d

H

8

H CO

0)

H CX
X CO

4J
CO

0)

0)

H

CO

43
CX

43
0)

e^

i-i
o

13

P d

J>^

O

^i

>^

H

\^x

o

_Zl*

0)

M

43

H >,

J

J3

43

H CO

JX,

rH

rH

0)

r *

(3 C

cu

TJ rH

o

CU

CU

-o cu

rH

cd

cd

O

I-l

CD

01

cu

CU -H
00 CU
O >H
M

si

<4-l 4-1

(3

o

T3
H

rH

cd
g

M ">.
3 43
M-l 0)
rH 'O

rH

cd

3

4-1
j

0)

43

1-4

0)

43

T-I

H
O

fll

1

(U

a

M

H y
Z cd

O

<4-l

3 -H
CO >

CJ

co "cd

PH

H

5?

H
33

W

CX
C/3

13
O

43

H

0)

3
^H

rH

/ **

S

S

3

^

O

O

o

OO

o

m

m

30

CT>

CM

30

00

CM

^3

vO

oo

p*>

'M

-^

H

P

.

in

m

in m

m

J

^o

^

m

vD

m

sf

01

Cu

r< S

C

1

M

CX

O

4-1

H

CO

O

Q

01 cd

rH

^S

iH N

m

4J

43

^.j.

-d" in

-o

vO

rH

m

^

Cd 4J

rH

o o

<!

rH

rH

m

o

O

o

in

m

4-1 S CO

o P! ex cu

o

O

O

o

CD

CD

o

o

H

0) O CXv_x

o

4J

M
4-1

01 4J

n cd

H

CU

rH 4J

43

cd ti

O
4-1

00) rH

HO S

m

m

m

m

rH

g

13 C -,

CM

H

rH -H

rH

fO

si-

1*-

rH

o

rH

^

l-i

O

4-
CX

8 3

o

O O

rH

CD

rH

CD

CD

o

r-l

M-l 01

O

Q "cx

^J

4-1

rH CO

O

CO CO

cx

^

I

rH T)

C/3

C3

o

(3

4J

4J CO

,_!

CX

cd

O

.

43

0)

n o

M'ci

P^

.^

I t

1 rJ --N

G cd

^t

H

I

43 /"N

.,_!

O CO CU

^-1 rH

}-l

O

CU

O

CX T3

3

C rH

rH 43

i

cd

01

H

^

cd -H
13 o

T3

H

H 1 O

g m N

01

CX

B C2

fH

o

H

N

g

1 cd

H

i^

cd i cd

c

CO CU

5

H

rH

cd

CO

CM

O

0)

I -H

o

CQ cu

rr

CX

H

1

1

cd

C

e

<V 13 M

4-1

Jj

t/j

O

(3

rQ

>>rt

I

0)

CO

v^- -H 4J

cu

C 4-1

cd

^

\^s

X C

rH

43

N |

O 0)

4J

CO

,J

7

CX

T3 cd *^

cd

43

8

43
0)

hromo

l-i

cd
cd

rH
01

-a

H

o
f

T3 H
>> 3
43 CO

0)

43

13
0)

1

O
4J
CX

E-

r-i ^ >
CO TJ CM

H J3 <H

3

rH

4-)
CU
U

13
01 4J
CO -H

cd ti
a* 3

fX,

PL,

Pi

cx|

EH

s

PH

<!

cd

145

146

Intersociety Committee 10 for determining formaldehyde concentration
in occupational environments.

The chromotropic acid method suggested by NIOSH and the
Intersociety Committee involves the collection of samples by passage
of air through two midget impingers in series, each of which contains
20 ml of distilled water. When a suitable volume of air has been
sampled (1 h of sampling at 1 slpm) , the contents of the midget
impingers are analyzed separately. For analysis, the contents of an
impinger are diluted quantitatively to a known volume. With 1%
chromotropic acid, an aliquot of the sample is brought up to 0.025%
chromotropic acid. Concentrated sulfuric acid is then added at 3
parts acid to 2 parts sample. The heat of mixing develops the color;
after cooling of the sample, the absorbance is read at 580 nm
(extinction coefficient, e/ 8.9 x 10 3 ) .

The reported sensitivity of the method is 0.1 ug/ml of
color-developed solution, which corresponds to formaldehyde at
approximately 0.04 ppm in the sampled air (see Table 6-2). Acrolein
is reported to be a positive interference at few percent. Ethanol,
higher-molecular-weight alcohols, and phenols can be negative
interferences, but at concentrations not normally encountered in the
atmosphere. Olefins in tenfold excess over formaldehyde can be
negative interferences at approximately 10%. Aromatic hydrocarbons
also constitute a negative interference. With the exception of
olefins, the interferences listed are not likely to be encountered in
substantial concentrations during atmospheric sampling. And even in
the case of olefins, the interference is not serious. 129

Early work by Altshuller et al. 8 indicated that nitrogen dioxide
did not interfere. However, the same cannot be said for nitrite and
nitrate. Indeed, there is a chromotropic acid assay for nitrate
similar to the formaldehyde assay. llfl * Cares 28 was the first to
investigate systematically the nature of the nitrite and nitrate
interference and methods of eliminating it. She found that both
interfered with formaldehyde analysis nitrite slightly more than
nitrate. When they were present in tenfold molar excess, negative
interferences of 60% and 30%, respectively were observed. Later work
by Krug and Hirt 72 confirmed these findings. To overcome these
interferences, Cares recommended a modified procedure that uses a
solution of sodium bisulfite for sampling. This solution is
neutralized and heated to reduce the oxides of nitrogen to nitric
oxide, which outgasses from the solution. The sample is then analyzed
as before, with chromotropic acid and sulfuric acid. This procedure
has not been used in field studies, probably because of its complexity.

Oxides of nitrogen can probably interfere with analysis for
formaldehyde with chromotropic acid. There is evidence that a major
sink for NC^ in the atmosphere involves its transformation to nitric
acid (or its subsequent transformation to nitrate-containing aerosols)
by way of OH attached on nitrogen dioxide. Furthermore, nitrogen
dioxide can be converted to nitrite and nitrate in the presence of
water or sulfuric acid, 33 integral constituents of the analytic
method.

147

It is not clear that the tentatively suggested method is
optimized. Bricker and Johnson, 25 who originally developed a
procedure using chromotropic acid, reported that full color
development depended on heating of the reaction mixture for 30 min.
Later work by West and Sen 11 * 5 and Altshuller et al . 8 suggested
that the heat generated by the mixing of concentrated sulfuric acid
with the sample solution was sufficient to drive the color -development
reaction to completion. This conclusion is open to question, inasmuch
as the peak temperature and duration of heating could be affected by
the choice of reaction vessel and by the ambient temperature. Bricker
and Johnson 25 also reported that the sulfuric acid concentration
should be at least 67% for maximal color development. West and
Sen, i<tS however, reported that color development increased strongly
with increasing sulfuric acid concentration until a value of 85% was
reached, after which the dependence lessened. This finding was
acknowledged by Altshuller et al. , e who went so far as to recommend
that samples be collected with impingers containing chromotropic acid
in concentrated sulfuric acid. Later simplex optimization work by
Olansky and Deming 9 6 indicated that color development is maximal at
57% and declines at higher values.

In sum, it seems that the chromotropic acid method suffers from
several deficiencies. It is not clear that the procedure is optimized
for maximal sensitivity; the method suffers from interferences by a
number of substances, some of which will undoubtedly be encountered
during field sampling; and modifications designed to reduce these
interferences introduce additional complexities.

Pararosaniline

A second reagent used for the measurement of formaldehyde
concentrations is pararosaniline, which was first introduced in the
form of a spot test by Schiff (1866 ). 120 In the classical Schiff
test for aldehydes, the intense pink color of basic fuchsin is
bleached with sulfur dioxide in basic solution. When an aldehyde is
added to the solution, it reverses the bleaching process, and the
basic fuchsin color returns. This spot test is neither quantitative
nor formaldehyde-specific.

Lyles, Dowling, and Blanchard 811 were the first to develop a
pararosaniline technique that produced a stable color and reproducible
results. The technique is as follows. Samples are generated by
passing air through a midget impinger containing distilled water. A
reagent solution containing 0.05 M tetrachloromercurate II and 0.025%
sodium sulfite is mixed with the sample in a ratio of 1 to 10. A
second reagent solution, prepared by dissolving 0.16 g of
pararosaniline and 24 ml of concentrated hydrochloric acid in water
sufficient to total 0.1 L, is added to the sample in a ratio of 1 to
11. After 15 min, the absorbence is read at 560 nm.

Several aspects of this analysis require comment. Lyles et al.
took note of earlier work 95 llt3 and were careful to use pure
pararosaniline in place of basic fuchsin reagent. The latter is often

148

contaminated with pararosaniline and is difficult to purify. Earlier
problems with reagent stability and reproducibility may have resulted
from insufficient purity.

The use of tetrachloromercurate II follows the work of West and
Gaeke, 1 * 3 who used pararosaniline in conjunction with formaldehyde
to determine sulfur dioxide. West and Gaeke sampled atmospheric
sulfur dioxide by bubbling air through a solution of sodium
tetrachloromercurate II. The sulfur dioxide was trapped and
stabilized as a dichlorosulf itomercurate II complex, which then
reacted with acidic pararosaniline and formaldehyde.

The pararosaniline method developed by Lyles et_ al_. 8 is
substantially the same as that used by the Combustion Engineering
Associates (CEA) 555 continuous analyzer. The latter is used by many
industrial hygienists to determine formaldehyde in workplace
environments. Its primary virtue is its ability to give nearly
real-time measurements.

Recent work has led to further refinements in the pararosaniline
technique. Miksch et al. took note of the work of Lahmann and
Jander, 73 German workers who investigated the dependence of the
technique of Lyles et al. on each of the reagents used. In
particular, the stability and sensitivity of the method could be
markedly improved through a fivefold reduction in the sodium sulfite
concentration. Substantial temperature effects on both stability and
time of development of the color were also noted.

In the same study, Miksch et al. questioned the use of
tetrachloromercurate II. Because the original role of this reagent
had been to stabilize the sulfur dioxide collected in the procedure of
West and Gaeke, 11 * 3 its function during formaldehyde determinations
was not clear. Investigation revealed that reversing the order of
addition of the reagents permitted the hazardous mercury reagent to be
eliminated. No metal ion at all was found to be necessary.

The procedure developed by Miksch et^ al_. is as follows. Samples
are collected in impingers containing deionized distilled water. The
samples are collected, shipped back, and stored at 5C to enhance
sample stability before analysis. In the laboratory, the contents of
two impingers operated in series are pooled, and the solution is
diluted to a known volume. A reagent solution, prepared by dissolving
0.16 g of pararosaniline and 20 ml of concentrated hydrochloric acid
in water sufficient to total 100 ml, is added to an aliquot of the
sample in a ratio of 1 to 10. After 10 min, a second addition of 0.1%
sodium sulfite solution is added to the sample in a ratio of 1 to 11.
The reaction vessels are capped (to prevent outgassing of sulfur
dioxide), and the color is allowed to develop for 1 h. The absorbance
is then determined at 570 nm (extinction coefficient, 1.88 x 10 4 ) .

The procedure is specific for formaldehyde. Only sulfur dioxide,
an integral part of the procedure in the form of sulfite, constitutes
a potential interference. This interference can be largely removed by
basifying the impinger solutions with 1 or 2 drops of 1 N sodium
hydroxide before analysis to destroy any formaldehyde-sulfur dioxide
adduct. This allows ambient concentrations of sulfur dioxide up to
500 ppb higher than normally encountered to be tolerated. Miksch et

149

al. nave reliably used the pararosaniline procedure in measuring
several thousand indoor and outdoor air samples.

Acetylacetone

A very sensitive fluorimetric method for the determination of
formaldehyde is based on the Hantzsch reaction between acetylacetone
(2,4-pentanedione) , ammonia, and formaldehyde to form
3,5-diacetyl-l,4-dihydrolutidine. The reagent was first used in a
colorimetric procedure by Nash, 911 who also reported that the adduct
fluoresced. Belman 1 9 developed a fluorimetric procedure based on
this property.

The procedure of Belman 19 is as follows: Equal volumes of
formaldehyde solution and a reagent consisting of 2 M ammonium acetate
and 0.02 M acetylacetone (pH, 6) are mixed and incubated at 37C for 1
h. After cooling to room temperature, the fluorescence is determined
(Xexcite = 41 nm ' *emit * 51 nm ) Tne standard curve is
linear with formaldehyde from 0.005 yg/ml to about 0.4 yg/ml and
deviates slightly from linearity from 0.4 \ig/ml to 1.0 yg/ml.
Above 1.0 yg/ml, the formaldehyde can be determined color imetrically.

This method has been particularly chosen by the wood industry in
determining emission from particleboard and plywood. 20 90 Under
controlled conditions in specially designed chambers, the formaldehyde
content of headspace vapor over materials being examined is
determined. This test is being considered for promulgation as a
European standard. 113 Acetylacetone has not been used for sampling
for formaldehyde in ambient air. In this application, possible
interference by oxides of nitrogen, sulfur dioxide, and ozone must be
considered. 9

Other Methods

It has already been mentioned that there are a fairly large number
of spectrophotometric methods for the determination of formaldehyde,
in addition to the two discussed above. In general, these methods
either have not been fully evaluated or suffer from major defects.
Several alternative wet-chemistry spectrophotometric methods of
analysis are listed in Table 6-2. Closely analogous methods, based on
spectrofluorometry, have also been suggested, as shown in Table 6-3.
One final analogous method deserving serious consideration is based on
chemiluminescence. All these methods are discussed below.

An older reagent that has been considered as a candidate for the
colorimetric determination of formaldehyde is phenylhydrazine.
Reaction of this reagent with formaldehyde, followed by oxidation of
the adduct with ferricyanide, leads to the formation of an anionic
species absorbing at 512 nm. 88 The essential drawback encountered
is that color is not stable and fades with time. Under some
procedural conditions, aliphatic aldehydes interfere. 13 * Other
possible interferences have not been investigated.

cu

T3

cu

CJ

a

CU

*

<J-

-*

>-i

rH

rH

rH

cu

II 1

rH

rH

rH

cu

aJ

CO

M

CO

CO

CO

CU

cu

M

T)

T3

D

GO

^

O

cu

Js

_rj

CU

o

CU

cu

^

c

T3

a

D.

cu

d

rH

cd

CU

c

cu

*Tj

H

4-1

M

^

^

CU

1-1

CU

cu

X

H

cu

X

cu

O

4J

00

00

T3

d

M

H
ffi

H

33

5!

CJ

cu a

u H

>> cu

x: H

cu o

13 Jj

CJ

cu
a
en

O
CO

8

m

o

cu
o

C

cu

cu
m

M-l

OO
v>

W

i

thods of Analysis for Fo

fluorometric

O
V
G,
CO

ission

460

O

CN

m

QJ

4J

m

o

H

O>1

a

en

-3-

X!

<u S

* fi

d 1

r^

B

H 5J

rQ 53

o

O

cd ^

4J

o c

cu o

W H

0) 4-1

o cd

j-i

rH 4J

(d C

e cu H

HOB

00

C (3 -^

CN

O

H O 00

S u a,

d

d

O
CNI

m

CN

m

H

m

O

rH

m

r^
-a-

CN

CN

O

m

o
o

13
V-i

o
cu
p

g

cd

c

m

CM

o

4-1

c

Jj
o

<+4 CU

e^
fx a

CO

S

x

cu
o

CO

rH m

X H

4-1 I
CU 0)

a g

d -H

I 13

m <u
> c

$

cu

. 5

tf 4J

t

c

a-o

1 1

x a

O

H TJ

o >,
cd X

c

4J Cd

cd

H H
rH J3

a

fa
cu

CO flj

c2
o cu

13

CU 4J
CO -H

cd c
d

150

151

A reagent similar to chromotropic acid in both its structure and
its associated analytic technique is 7-amino-4-hydroxy-2-
naphthalenesulfonic acid (J-acid). 116 The adduct formed is
fluorescent, and a second, more sensitive, technique that takes
advantage of this property has been developed. 118 Formaldehyde
precursors interfere under the harsh conditions of both these
techniques, and acrolein also interferes with the second technique.
Other possible interferences have not been adequately investigated.
The reagent phenyl-J-acid is a minor modification of J-acid. 116

Two other reagents must be mentioned as potential candidates for
the wet-chemistry determination of formaldehyde, although they have
not been adequately tested. The reagent phenylenediamine may be
oxidized by hydrogen peroxide to produce Bandrowski's base, 3,6-bis(4-
aminophenylimino)cyclohexa-l,4-diene-l,4-diamine U ma x' 485 nm) .
The reaction is catalyzed by formaldehyde 12 and may form the basis
for an analytic procedure. At present, only sulfur dioxide in
100-fold excess is known to interfere. The second reagent is
tryptophan, which reacts with formaldehyde in the presence of
concentrated sulfuric acid and iron to give a colored species. 30
The reaction was found to be extremely sensitive and free of
interference from a wide range of compounds, but its suitability as a
field sampling method has not been tested. The instability of some of
the reagents used may present a problem.

Two final reagents have occasionally been used to assay for
formaldehyde: 3-methyl-2-benzothiazolone hydrazone (MBTH) and
4-amino-3-hydrazino-5-mercapto-l,2,4-triazole (Purpald) . They are
specific only for the class of aliphatic aldehydes as a whole, and
precautions must be taken to ensure that separate formaldehyde is the
only aldehyde present. These reagents are discussed more fully in the
next section.

Several workers have attempted to develop fluorometric methods of
analysis for the determination of formaldehyde. The better known
examples are shown in Table 6-3. In general, the techniques are
sensitive to the design of the instrument note the different
sensitivities reported for the same reagent at different times. The
later work actually shows reduced sensitivity. Problems common to
many fluorescence techniques are susceptibility to sample matrix
variations and nonlinear standard curves. With the exception of
acetylacetone, none of the reagents shown has been used in reported
studies.

A final method deserving serious consideration is based on a
chemiluminescent reaction of formaldehyde and gallic acid in the
presence of alkaline peroxide. 128 In a flow system where the
reagents can be mixed immediately before passage into an optical cell,
formaldehyde concentrations as low as 3.0 ng/ml can be detected an
increase in sensitivity of more than an order of magnitude relative to
the color imetric procedures just described. A second distinct
advantage is that the working linear range of response extends over
five orders of magnitude.

The chemiluminescence method may not be completely
formaldehyde-specific. Acetaldehyde was reported to give a response

152

that was less than one-tenth that of formaldehyde. Other aldehydes
were not tested. Two dicarbonyl compounds, glyoxal and methylglyoxal,
gave a response equal in magnitude to that of formaldehyde. lze
These compounds would not normally be encountered, except perhaps in
biologic samples.

Proper design of the flow system and optical cell are essential to
the chemiluminescence method. With proper design, the apparatus can
be inexpensive. The method is best suited to analyzing aqueous
impinger solutions at a central laboratory or to continuous monitoring
at selected stationary sites (C.D. Hollowell, personal communication).

TOTAL ALIPHATIC ALDEHYDES

Measurements of total aliphatic aldehydes are based on chemical
reaction behavior imparted by the presence of the formyl group common
to all aldehydes. As with formaldehyde, only wet-chemistry
spectrophotometric techniques have been used for sampling total
aliphatic aldehydes under field conditions. The application of more
sophisticated instrumental techniques to the determination of total
aliphatic aldehydes is inadvisable, because it is usually easier and
more desirable to identify and measure each specific aldehyde
separately.

3-Methyl-2-benzothiazolone Hydrazone

By far the most commonly used reagent for the determination of
total aliphatic aldehydes is MBTH. First introduced by Sawicki e_t
al. , 117 this reagent has been used for measuring lower-molecular-
weight aliphatic aldehydes in auto exhaust and urban atmospheres (see
Table 6-2) .

A tentative method using MBTH for determining aldehydes in ambient
air was given by the Intersociety Committee. 10 The method is as
follows. Air to be sampled is bubbled through 0.05% aqueous MBTH
contained in a midget impinger. After dilution to a known volume, an
aliquot of an oxidizing reagent containing sulfamic acid and ferric
chloride is added. After 12 min, the absorbence is read at 628 nm.
At the recommended sampling rate of 0.5 slpm, assuming a minimal
detectable absorbence change of 0.05 unit, a concentration of 0.03 ppm
could be determined after sampling air for 1 h.

The original method of Sawicki e_t al^ 117 used ferric chloride
alone as the oxidizing reagent. Because of turbidity, acetone was
incorporated into the dilution scheme. Hauser and Cummins 53
effectively eliminated the turbidity by adding sulfaraic acid to the
oxidizing reagent. The molar absorptivities of the aldehydic adducts
formed vary between approximately 48,000 and 56,000. The formaldehyde
adduct has a molar absorptivity of 65,000. Altshuller et al. 3
recommended that concentrations of aldehydes determined by MBTH should
be multiplied by a factor of 1.25 to account for the difference in

153

response between formaldehyde and the remaining aliphatic aldehydes.
The recommendation has not been followed in reported uses of MBTH.

Many classes of compounds, particularly those containing nitrogen,
react with MBTH to give colored products. Most of these compounds are
not encountered during atmospheric sampling. Nitrogen dioxide has
been reported to interfere through formation of nitrite and nitrate in
water .

Purpald

A reagent recently developed for the determination of aliphatic
aldehydes is Purpald. First described by Dickinson and Jacobsen, 35
the reagent can be used quantitatively as follows. 62 A basic
solution of Purpald is added to aqueous samples containing
formaldehyde. The mixture is aerated for 30 min to ensure oxidation,
and the absorbence is determined at 549 nm. Assuming that impingers
are used for sampling air at a rate of 1 slpm for 1 h and that the
minimal detectable absorbence difference is 0.05 unit, a concentration
of 0.04 ppm can be detected. Purpald suffers from the same drawback
as MBTH: it gives different responses to different aldehydes.
Potential interfering substances encountered in atmospheric sampling
have not been completely examined, but no interference from a wide
variety of test compounds was noted by the originators. 35

Other Methods

2,4-Dinitrophenylhydrazine (DNPH) has received considerable
attention as a reagent for determining aldehyde concentrations. The
vast majority of DNPH techniques attempt to separate and identify the
individual aldehydic adducts through the use of thin-layer
chromatography, gas chromatography, or high-performance liquid
chromatography . Wet-chemistry spectrophotometric procedures are based
on the formation of a chromogen absorbing at 440 nm. 100 10S These
procedures have been hampered by the interference of ketones and
problems with reagent stability. The minimal detectable concentration
of aldehydes with these procedures is about 0.2 ppm.

A method deserving mention is the bisulfite method published by
the Los Angeles Air Pollution Control District. 7 * Air is sampled
with impingers containing aqueous bisulfite. The aldehydes react to
form aldehyde- bisulfite adducts. The excess bisulfite is destroyed,
and the solution is basified to liberate the bisulfite bound in the
adducts. The freed sulfite is titrated with iodine and starch. The
method is cumbersome, the adducts are not stable for long periods even
if kept on ice, and the iodine reagent is sensitive to air and light.

154

ACROLEIN

Acrolein is a highly toxic aldehyde; a threshold limit value (TLV)
of 0.1 ppm f has been established by the Occupational Health and Safety
Administration (OSHA). 1 " This standard is 30-fold lower than the
corresponding TLV for formaldehyde. Acrolein is the only aldehyde
other than formaldehyde for which there is a specific wet-chemistry
spectrophotometnc method of analysis.

4-Hexylresorcinol

The most popular method for determining acrolein in air uses
4-hexylresorcinol. 31 68 139 Air is typically drawn through two
midget impingers at 1 slpm to collect the sample. The collecting
solution can be either 1% sodium bisulfite or a reagent containing
4-hexylresorcinol, mercuric chloride, and trichloroacetic acid in
ethanol. Samples collected in bisulfite are analyzed by adding
4-hexylresorcinol and mercuric chloride in ethanol and then a solution
of trichloroacetic acid in ethanol. The solution is heated for 15 mm
at 60C, and the resulting color is measured at 605 nm. Samples
collected in 4-hexylresorcinol are analyzed simply by heating and
measuring the color. For field sampling, the simplicity of the latter
method is offset by the hazards of handling the toxic and corrosive
reagent. In addition, the reagent and the samples collected are not
very stable, and samples must be analyzed within a few hours. The
bisulfite method is somewhat more complex, but it is safer to use.
Besides using a less hazardous collecting solution, this method
produces samples that are stable for up to 48 h if they are kept
refrigerated, thus permitting later analysis at a central laboratory.

A recent paper by Hemenway et al. 5I pointed out a potential flaw
in the 4-hexylresorcinol method given by NIOSH. 139 Apparently, the
order of addition of reagents for analysis differs between field
samples and calibrating solutions, and this may lead to
underestimation by as much as 35%. The validity of this objection
needs to be established.

Other Methods

A very sensitive procedure for the determination of acrolein is a
fluorimetric method using m-aminophenol . 1 The procedure can detect
acrolein at concentrations as low as 10 ng/ml in an aqueous test
solution. No interference is reported for many alcohols, amines,
ammo acids, and polyamines. Other aldehydes do not interfere unless
they have a double bond in conjugation with the formyl group analogous
to acrolein (e.g., crotonaldehyde) . The procedure shows promise, but
has not been applied to environmental samples.

Chromotropic acid has also been suggested for acrolein
determinations. H9 In the formaldehyde procedure using Chromotropic
acid, the response to acrolein is regarded as an interference;

155

however, the absorbance maximums are sufficiently different that it i
possible to measure the two compounds separately. A method for the
simultaneous determination of formaldehyde and acrolein in air has
been proposed by Szelejewska. 1 3 3 Samples are collected in bisulfite
at 1 slpm before the addition of chromotropic acid in sulfuric acid.
After the addition of the chromotropic acid reagent, the absorbance i
measured at both 420 and 575 nm. The two absorbances are fitted to a
linear system of two equations that, when solved, gives the
concentrations of the two aldehydes. This method has not been used i
practice.

Two other reagents for the analysis of acrolein have been
discussed by Cohen and Altshuller . 3 l The first, phloroglucinol,
reacts with acrolein to produce a red color. The reaction is subject
to interference from formaldehyde and oxides of nitrogen and has not
been used. The second, tryptophan, reacts with acrolein in acid
solution to produce a purple color. The sensitivity of the tryptopha
method is only one-fourth that of the 4-hexylresorcinol method.
Furthermore, in view of the fact that a similar method has recently
been used to determine formaldehyde, 30 the reagent may be subject to
interference from formaldehyde.

ACETALDEHYDE

The only color imetric method reported to be specific for
acetaldehyde uses diazobenzene sulfonic acid. 11 * 2 Unfortunately, no
data are available on the sensitivity or interferences associated wi
this method. Some efforts have been made to take advantage of the
rather high volatility of acetaldehyde, in separating it by
distillation from other aldehydes. Procedures that use this method
are too cumbersome to be reliable. A method has recently been
published for determining acetaldehyde in the presence of formaldehy
in biologic materials. 91 * Acetylacetone reacts with the solution,
which eliminates the formaldehyde, and then the acetaldehyde is
analyzed with p_-phenyl phenol. This method does not take into accou
interferences from higher aldehydes; it is not actually a procedure
for acetaldehyde, but rather for nonformaldehyde aldehydes. The onl
methods available for determining acetaldehyde involve the separatic
of all the aldehydes that are present with gas or liquid
c h r oma tog r aphy .

OTHER ANALYTICAL METHODS

SPECTROSCOPIC METHODS

Microwave, infrared, and laser-fluorescence spectroscopy have aJ
been used to measure aldehyde concentrations in ambient air directls
Each of the methods is prohibitively expensive for ordinary field
sampling. The instrumentation required is often cumbersome and

156

delicate, is seldom portable, and requires sophisticated maintenance
and support facilities.

Microwave rotational spectroscopy can measure low concentrations
of many compounds in gas-phase samples. Rotational resonances are
very sharp at microwave frequencies and low partial pressures, so
sample spectra can be easily resolved. Formaldehyde has been
monitored continuously at concentrations as low as 10 ppb in air with
a two-stage membrane separator for preconcentration. s 7 Acetaldehyde
has been detected directly at 15 ppm. 58 This is far above normal
concentrations for ambient air, and the technique is not routinely
applicable to ambient-air analysis. Microwave spectroscopy has also
been used to determine acrolein, acetaldehyde, and formaldehyde in
tobacco smoke. 66 The sensitivity of the technique was reported to
be 2 ppm, but, again, this concentration is rather high and would not
normally be encountered in ambient air. Furthermore, the response
time of the instrument is long, rendering the technique insensitive to
changes in concentrations.

Infrared spectroscopy is promising, owing to the sharpness of the
rotational and vibrational peaks observed for gas-phase samples.
Unfortunately, good spectral resolution (less than 0.1 cm" ) and
rapid measurements are hampered by the low power of infrared sources.
To overcome this difficulty, Fourier-transform infrared (FTIR) methods
have been developed in which conventional Fourier-transform methods
are used to derive the absorption bands. FTIR instruments are
commercially available, but are exceedingly expensive. In one
application, formaldehyde was continuously monitored at ambient
concentrations of less than 10 ppb with an FTIR system. 137 The
system was used with a Michelson infrared interferometer with a
sophisticated multiple-reflection optical cell whose pathlength was 2
km. Longer pathlengths could not be obtained, because of image
overlap. Other aldehydes were not measured.

A fluorescence procedure based on the direct excitation of
formaldehyde by a dye laser has been reported. 15 Formaldehyde as
low as 50 ppb in air could be detected. The authors suggested that
further refinements would increase the sensitivity. The application
of this technique to other aldehydes is restricted by the weaker and
less well-resolved absorption spectra in the accessible spectral
region.

CHROMATOGRAPHIC METHODS

Three chroma tographic techniques have been applied to the analysis
of aldehydes: gas chroma tography, liquid chroma tography, and ion
chroma tography. Gas -chroma tographic analysis of aldehydes generally
takes one of two forms: direct analysis by gas or solution injection
and derivatization followed by analysis.

Formaldehyde presents special problems with respect to direct
analysis by injection. In a flame ionization detector (FID), a
universal detector widely used for quantitative work, formaldehyde
decomposes and gives a very small response. Thermal conductivity

157

detectors (TCDs) are less sensitive and respond only to very high
concentrations of formaldehyde. An electron capture detector (ECD)
has a limited linear response range and is sensitive only to
conjugated carbonyl groups. The photoionization detector (PID) is
reported to be sensitive to formaldehyde (HNU Company, Newton Upper
Falls, Mass.), but appears to have some drawbacks. Specifically, a
high-energy lamp is required to detect formaldehyde; this drastically
reduces both the selectivity and the lifetime of the detector. 96

In principle, it is possible to circumvent the insensitivity of
the FID to formaldehyde by catalytically reducing formaldehyde to
easily detectable methane. 32 Because hydrogen is required for the
operation of the FID, the reduction is easily achieved by passing a
mixture of the column effluent and hydrogen gas over a short bed of
catalyst before introduction into the FID. Deposits of nickel,
thorium, and ruthenium on fine-mesh glass beads have all been used
successfully to reduce formaldehyde to methane. The lack of success
in applying the technique to routine analysis of formaldehyde can be
attributed to problems in choosing proper gas-chromatographic
conditions. Apparently, it is difficult to pass formaldehyde through
any of a variety of column -pack ing materials quantitatively. 26

With the exception of formaldehyde, aldehydes may be analyzed by
direct gas injection if concentrations are high enough. By using a
six-port valve equipped with a 1-ml gas-sampling loop, aldehydes can
be routinely detected with an FID at concentrations as low as 0.03 pp
without preconcentration (Analytical Instrument Development, Inc.,
Avondale, Pa.). It is important to recall, however, that gas
chromatography excels at separation, but provides minimal
identification. Ambient-air samples often contain hydrocarbons, and
their responses may overlap and obscure the aldehydic responses.
Bellar and Sigsby 18 reported a complex automated gas chromatographic
technique to analyze for C 2 -C 5 aldehydes that avoided this
problem. Hydrocarbons and aldehydes from an air sample flowed onto
polar cutter column, where the aldehydes were retained as the
hydrocarbons were passed through and vented. The cutter column was
then backflushed to a cryogenic trap, where the aldehydes were
reconcentrated before introduction onto an analytic column. About ar
hour was required for a complete analysis. The method has not been
used by other workers.

Preconcentration before direct analysis has also been
investigated. Pellizzari 1 3 101 * has reported the collection of some
higher-raolecular-weight aldehydes on Tenax-GC. After thermal
desorption and reconcentration in a cryogenic trap, analysis is
performed by gas chroma tography/mass spectrometry. The method
provided poor quantification. Gold e_t al^ * successfully captured
acrolein on molecular sieves. The sieves were desorbed with water,
which was then injected onto a column packed with hydrophobia
Tenax-GC. The method has not been used by other workers.

Derivatization is an alternative technique that has been
extensively investigated. Levaggi and Feldstein 78 introduced a
method in which samples were collected with impingers containing 1%
sodium bisulfite solution. Aldehydes react with the bisulfite to fori

158

adducts. Formaldehyde and acrolein are analyzed by chromo tropic acid
and 4-hexylresorcinol methods, respectively. To analyze the remaining
aldehyde, the bisulfite solution is injected onto a packed column in a
gas chroma tograph. Samples must be kept cold to prevent
deterioration. The Intersociety Committee 10 has adapted the
technique as a tentative method for the ^-5 aldehydes, but there
are no reported uses in the literature. A problem not explicitly
discussed is the rapid degradation of column performance due to the in
situ production of sulfur dioxide and sodium hydroxide as the adduct
thermally decomposes.

Much work has been aimed at using 2,4-dinitrophenylhydrazone
(DNPH) derivatives of aldehydes, well known for many years for their
use in the qualitative identification of aldehydes. DNPH reacts with
aldehydes in aqueous solution to form precipitates. In most attempts,
this precipitate is redissolved in an organic solvent, which is then
injected into a gas chroma tograph. The resulting chroma tog rams show
double peaks for each derivative corresponding to the syn- and anti-
isomers formed around the nitrogen-carbon double bond characteristic
of the derivative. These peaks are not symmetrical, because of steric
influences during formation of the derivative. The peaks observed for
the derivatives of propionaldehyde , acrolein, and acetone overlap and
are difficult to separate. The most consistent problem is the
verification that quantitative derivatization of the available
aldehydes has occurred.

DNPH was applied by Hoshika and Takata 55 to the analysis of
automobile exhaust and cigarette smoke. Papa and Turner 101 102 also
applied it to automobile exhaust. In a two-step process, preliminary
separation of DNPH aldehyde derivatives by preparative gas
chromatography was followed by analytic gas chromatography. 131 In
analyzing food samples, a number of workers have used glutaric acid
and flash-exchange gas chromatography to regenerate free aldehydes
from DNPH derivatives. 50 si es 6? BO 109

A variety of alternative derivatizing reagents have been
investigated. Gas chromatography of aldehydic derivatives of
phenylhydrazine 71 and 2,4,6-trichlorophenyl hydrazine 6 " has been
studied. These reagents are close analogues of DNPH. The aldehydic
derivatives of dimethylhydrazine, 6 3 hydroxylamine , 1% J and
tetramethyl ammonium acetyl hydrazide (Girard-T Reagent) ^ "* 6 97
have been analyzed with gas chromatography. Like DNPH, these reagents
all involve reaction of a free amine with the formyl group to form a
nitrogen-carbon double-bonded derivative.

Direct analysis of aldehydes with high-performance liquid
chromatography (HPLC) has not been thoroughly investigated, primarily
because of the lack of a detector with sufficient sensitivity. To
circumvent this problem, aldehydes can be made to react with DNPH to
form a derivative with a strong ultraviolet-absorption spectrum. This
approach has been investigated by Carey and Persinger , 29 Mansfield
e_t_al_. , 87 Selim, 126 and others.

Ion chromatography is a new technique (DIONEX, Inc., Sunnyvale,
Calif.) that has application to formaldehyde analysis, it combines
liquid chromatography with an ion-exchange column to separate charged

159

species. A conductivity detector provides excellent sensitivity.
Formaldehyde is captured on specially impregnated charcoal and then
desorbed with aqueous peroxide. The resulting formate ion can then be
analyzed by ion chroma tog raphy. Two ma;jor difficulties with the
method are ensuring quantitative recovery of formaldehyde from the
charcoal and preventing the peroxide reagent from oxidizing other
materials to formate ion.

ELECTROCHEMICAL METHODS

In addition to the usual techniques of analyzing organic
materials, aldehydes can be analyzed by electrochemical methods. Both
polarographic methods and amperometric titrations have been used.

Lupton and Lynch 83 developed polarographic techniques for the
analysis of aldehydes in a wide range of samples. McLean and
Holland 89 adapted their technique to a portable system for rapid
analysis of aldehydes in automotive exhaust sampled by bubbling into
water. The polarograph was rendered portable by replacing the
dropping mercury electrode with a quiescent mercury pool a few
millimeters in diameter. Analysis used the method of standard
additions. The procedure is not specific, however, even for aldehydes.
The authors suggested differential-pulse polarography for separation
of the aldehydes, but this has not been tested.

Ikeda 61 developed a short-circuit argentometric amperometric
titration for determining formaldehyde with a rotating platinum
electrode. Equimolar amounts of acetaldehyde produced substantial
interference, and other aldehydes may as well. The method is suitable
for measuring quantities of formaldehyde as low as 0.1 mg.

CURRENT APPLICATIONS OP ANALYTICAL METHODS

The standard techniques for analysis of aldehydes in use today
were developed for application in specific sampling situations. These
situations and the techniques used are discussed below.

AIR
Ambient Air

The wet-chemistry spectrophotometric methods of analysis have beei
used extensively for the analysis of aldehydes in ambient air. The
method based on MBTH has been applied to studies of total aliphatic
aldehydes in the ambient atmosphere and from emission sources. 5 7 108
As mentioned earlier, it has been recommended for the determination o
total aliphatic aldehydes by the Intersociety Committee. 10

Invariably in atmospheric or emission samples the principal
aldehyde detected is formaldehyde. The most extensively used
procedure is based on chromotropic acid. 6 ' 8 ll7 123 The
Intersociety Committee 10 and NIOSH 139 have recommended the use of

160

chromotropic acid. Schiff's reagent (basic fuchsin) and
pararosaniline also have been suggested for atmospheric
determinations. 73 B * 110

The high toxicity of acrolein has prompted analyses of this
aldehyde in atmospheric and emission samples. The only sufficiently
sensitive colorimetric method available for analysis of acrolein is
based on 4-hexylresorcinol, 2 31 a reagent that has been used 7 112 123
and is recommended by the Intersociety Committee. 10 A single
investigation used a gas-chroma tographic technique to determine
acrolein in ambient air. 18

Gasoline and Diesel Exhaust

The MBTH technique has been applied to automobile (gasoline) 1211 12S
and diesel 111 exhaust emission to determine the concentration of
total aliphatic aldehydes. Two titrimetric procedures have also been
used for auto-exhaust measurements. 39

The chromotropic acid method has been used widely for measuring
formaldehyde in automobile 1 *- 6 8 7S 117 125 and diesel 1 " * el 82
exhaust. The Schryver method, involving the reaction of formaldehyde
with phenylhydrazine followed by oxidation with potassium femcyanide
to form a red derivative, also has been used in studies of
formaldehyde emitted in automobile and diesel exhaust. 38 39

The acrolein content of automobile exhaust has been determined
with the 4-hexylresorcinol method. 3 13 31 75 Diesel-exhaust emission
has also been studied with this technique. 1 " 81 82 i11

Because of the relatively high concentrations of acrolein
encountered in automobile and diesel exhaust, this pollutant can be
effectively measured by gas-chromatographic techniques. Acrolein has
been determined directly and as a derivative. 18 " " 2 s9 60 12 "

Nonoccupational Indoor Air

Interest in measuring aldehyde concentrations in nonoccupational
indoor environments is a relatively recent phenomenon. Workers in
Europe were among the first to determine aldehyde and formaldehyde
concentrations in residences. In the Dnited States, attention has
been focused on formaldehyde emitted from urea-formaldehyde products
used in the construction of homes, especially mobile homes. Table 5-3
(in Chapter 5) summarizes the studies performed to date.

Formaldehyde concentrations were determined for residences in
Denmark, ^ the Netherlands, and the Federal Republic of
Germany. 1 " 8 Maximal concentrations observed in European dwellings
reached 2.3 ppm, but average concentrations were 0.4 ppm or less. 11 14
Interestingly, maximal formaldehyde concentrations in residences built
without formaldehyde-releasing materials in the Netherlands reached
only 0.08 ppm, and average concentrations were only 0.03 ppm. 1 " 8
Chromotropic acid was used most often in these European studies.

161

The MBTH technique was used to measure total aliphatic aldehydes
in a pair of mobile homes and a sample residence in Pittsburgh. 93
Breysse 21 * used the chromotropic acid method recommended by NIOSH to
sample 608 mobile homes in the state of Washington in which residents
had complained of irritation; the peak formaldehyde concentration
observed in an occupied home was 1.77 ppm, and the mean was less than
0.5 ppm. Garry et al. ** used the chromotropic acid method with a
shortened sampling time to assess formaldehyde concentrations in
Minnesota mobile homes. The state of Wisconsin also has used the
chromotropic acid method to sample in mobile homes in which residents
had registered complaints (M. Woodbury, personal communication) .

Systematic studies of formaldehyde and total aliphatic aldehydes
as pollutants in nonoccupational indoor environments have been
performed by the Lawrence Berkeley Laboratory (LBL) (Lin et al. 79
and Miksch e_t_ al_. , unpublished manuscript). LBL has used the MBTH
technique to determine total aliphatic aldehyde concentrations f and
the chromotropic acid technique and a modified pararosaniline
technique have been used to measure formaldehyde. Sampling sites hav
included conventional and energy-efficient homes (occupied and
unoccupied) and public buildings, such as schools, office buildings,
and hospitals.

Occupational Indoor Air

Only occupational air-quality formaldehyde standards are
recommended or promulgated by several agencies and professional
organizations in the United States. OSHA 1 * has promulgated an 8-h
time-weighted average (TWA) standard of 3 ppm. The American
Conference of Governmental Industrial Hygienists 9 has promulgated a
threshold limit value (TLV) standard of 2 ppm. NIOSH 138 has
recommended an exposure standard of no greater than 1 ppm for any
30-min sampling period.

The Intersociety Committee, 10 of which the ACGIH is a member,
and NIOSH 139 both recommend a method of analysis for formaldehyde
based on the use of chromotropic acid. Despite this recommendation,
workers investigating formaldehyde concentrations in occupational
environments have used a variety of techniques summarized in Table 5-
(in Chapter 5) .

Shipkovitz 127 investigated formaldehyde in textile plants where
fabric was treated with formaldehyde-containing resins. Samples wer<
generated by drawing air through bubblers containing sodium bisulfit*
solution and were analyzed by iodometric titration. The method was
reported to have a sensitivity of 0.5 ppm, but was not specific for
formaldehyde.

Collection in sodium bisulfite had been used earlier by the
California Department of Public Health 21 to analyze air at a textile
garment factory. The method of analysis was not reported. In the
same year, however, the California Department of Public Health
investigated airborne formaldehyde in a clothing store by using midg>

162

impingers containing a solution of MBTH. 9 1 As with sodium
bisulfite, this reagent is not specific for formaldehyde.

A modified chromotropic acid procedure was used by Schuck et
aJL. 121 to determine formaldehyde concentrations during a study of
the ocular effects induced by smog components. Subjects were exposed
to formaldehyde in a smog chamber. Chromotropic acid was used to
determine formaldehyde concentrations between 0.04 and 10.9 ppm at two
laminating plants using phenol-resorcinol glues. 1 * 1 * A survey of six
funeral homes used a modified chromotropic acid procedure, in which
air was bubbled into 0.1% chromotropic acid in concentrated sulfuric
acid, to determine exposure to formaldehyde during the embalming
process. 69 Reported concentrations of 0.09-5.26 ppm may have been
in error on the high side, inasmuch as no prefilter was used on
air-sampling lines to remove paraformaldehyde dust which was also
present.

WATER

Most of and perhaps all the methods that have been used to
identify or measure aldehydes in samples of air and biologic tissue
should be applicable to water samples; however, little research has
been performed to determine the relative accuracy, precision, or
sensitivity of the methods for measuring aldehydes in water.

Because of the high toxicity of acrolein to aquatic life, Kissel
and co-workers 70 evaluated several chemical analytical procedures by
comparing the analytical data with data from bioassays on acrolein.
Eight methods three derivatization and five direct were evaluated.
The derivatization methods were the bromide-iodide-thiosulfate
titration method of Pressman and Lucas, 106 the 2,4-dinitrophenyl-
hydrazine colorimetric method of Bowmer and co-workers, 22 and the
aminophenol fluorescence method of Alar con. J Direct measurements
were performed by ultraviolet spectrophotometry, 1 * 9 gas-liquid
chroma tography, 13 nuclear-magnetic-resonance spectroscopy,
differential-pulse polar ogr aphy, 5S and direct fluorescence. The
effect of different buffering systems on the toxicity and chemical
analysis of acrolein was also investigated.

Analytical data produced by the derivatization methods and by
gas-liquid chromatography did not correlate well with the bioassay
data. Often, no biologic responses were observed for test solutions
in which these methods indicated the presence of toxic concentrations
of acrolein. The direct ultraviolet spectrophotometric method was
also judged unsuitable, because it produced extraneous peaks, which
were often more intense than the acrolein peaks and tended to mask
them.

Data producted by nuclear-magnetic-resonance spectroscopy,
differential-pulse polarography, and direct fluorescence correlated
very well with the bioassay data. Assuming that the bioassay provided
a more realistic measure of the concentrations of acrolein in
solution, the authors concluded that these direct methods were
suitable for monitoring acrolein in water. How well these methods

163

will work for other aldehydes is unknown. Unfortunately, this study
appears to be the only published one concerning the suitability of
possible methods for measuring an aldehyde in water.

Gas chromatography, in combination with mass spectroscopy, appear
to be gaining favor over other techniques for identifying and
measuring aldehydes not only in water, but in plant material where
the chemical composition can be highly complex, which necessitates tt
isolation of the aldehyde from other components. Problems have been
encountered, however, when conventional gas-chroma tographic procedure
(such as use of packed columns) are used. Such columns are incapabl*
of resolving all the aldehydes present. For this reason, some
investigators have resorted to using thin-layer chromatography in
conjunction with gas chromatrography to obtain greater resolution.

The advent of the glass capillary column has essentially
eliminated the need for thin-layer/gas chromatography. Hollowell
(personal communication) used a gas chroma tog raph (Carlo Elba)
equipped with a 50-m 3 glass capillary column and a splitless
injector system in conjunction with a mass spectrometer (Finnigan,
Model 3200) to identify and measure aldehydes in drinking water of
various sources. The aldehydes were removed from the water samples
and concentrated in XAD columns (resin series not designated). The
eluting solvent was not reported, but presumably was benzene or ethy

acetate.

Although the gas-chromatographic system provided excellent
separation of the aldehydes, the electron-impact mass-spectroscopic
technique was not suitable for determining the exact structure (and
therefore identifying) a number of compounds with an apparent alkana
structure. With the system, Piet was able to identify 13 aldehydes;
their concentrations ranged from 0.005 to 0.3 ppb.

P^LANT MATERIAL

Two analytical methods have been used for measuring aldehydes, c
involving gas chromatography and the other, DNPH formation. For fri
products, an open tubular gas-chromatographic column with programed
temperature control has been used to separate volatile components,
stainless-steel tube coated with GE SF-96 (50-silicone) was used wi
grape juice. A copper tube packed with 10% Carbowax 20M on Halopori
was used in research with ginkgo leaves. A combination of infrared
spectra, retention data, and mass spectrometry was used to identify
and measure particular aldehydes.

in 1972, Major and Thomas 86 compared the amount of 2-hexenal in
ginkgo leaves as measured by gas chromatrography and by the weight
2,4-DNPH. He added the ether extracts of steam-distilled leaves to
solution of 2,4-DNPH, hydrochloric acid, and methyl alcohol. After
h, the solvents were evaporated to a small volume, and the
crystallized 2,4-DNPH was checked for purity by melting point and b
thin-layer chromatography (TLC) on silica gel with 6:1 hexanerether

164

as the developer. Recovery by DNPH was inferior to that by the
gas-chromatographic method.

Winter and Sundt, 1 " 7 leaders in investigation of strawberry
flavors, have objected to the use of gas chroma tog raphy in aldehyde
analysis, because it operates at a relatively high temperature and
product modifications may result under these conditions. They favor
paper chroma tog raphy, because the volatile constituents are fixed
rapidly by derivative formation and thus protected from further
changes. They have identified the isolated derivatives by melting
point and by infrared spectroscopy.

In 1976, Braddock and Kesterson 23 used a more sophisticated
2,4-DNPH method than reported by Manor and Thomas. Cold-pressed
citrus oils dissolved in hexene were applied to a bed of a 2,4-DNPH
reaction column. A volume of about 500 ml was eluted and aliquots
were chromatographed on consecutive columns of Celite-Seasorb and
alumina. Column effluents were evaporated to dryness and taken up in
chloroform, and the absorbence was determined for estimation of
quantities of 2,4-DNPH by the extinction coefficients. Effluents from
the alumina columns were separated by thin-layer chromatography into
individual aldehyde 2,4-DNPHs. Each aldehyde was scraped from the TLC
plates and measured by its extinction coefficient. Tentative
identification of individual aldehyde 2,4-DNPHs was by comparison of
Rf values with standard derivatives. Aldehyde 2,4-DNPHs scraped
from TLC plates were identified positively by comparing mass spectra
of known derivatives with the unknowns.

REFERENCES

Alarcon, R. A. Fluorometric determination of acrolein and
related compounds with m-aminophenol . Anal. Chem. 40:1704-1708,
1968.

Altshuller, A. P. Detection of acrolein in automobile exhaust
and the atmosphere. Int. J. Air Water Pollut. 6:169-170, 1962.
Altshuller, A. p., I. R. Cohen, M. E. Meyer, and A. F. Wartburg,
Jr. Analysis of aliphatic aldehydes in source effluents and in
the atmosphere. Anal. Chim. Acta 25:101-117, 1961.
Altshuller, A. P., S. L. Kopszynski, W. Lonneman, and D.
Wilson. Photochemical reactivities of exhausts from 1966 model
automobiles equipped to reduce hydrocarbon emissions. J. Air
Pollut. Control Assoc. 17:734-737, 1967.
Altshuller, A. P., and L. J. Leng. Application of the
3-methyl-2-benzothiazolone hydrazone method for atmospheric
analysis of aliphatic aldehydes. Anal. Chem. 35:1541-1542, 1963
Altshuller, A. P., L. J. Leng, and A. F. Wartburg, Jr. Source
and atmospheric analyses for formaldehyde by chromotropic acid
procedures. Int. J. Air Water Pollut. 6:381-385, 1962.
Altshuller, A. P., and S. P. McPherson. Spec tropho tome trie
analysis of aldehydes in the Los Angeles atmosphere. J. Air
Pollut. Control Assoc. 13:109-111, 1963.

165

8. Altshuller, A. P., D. L. Miller, and S. F. Sleva. Determination
of formaldehyde in gas mixtures by the chromotropic acid
method. Anal. Chem. 33:621-625, 1961.

9. American Conference of Governmental Industrial Hygienists.
TLV S . Threshold Limit Values for Chemical Substances and
Physical Agents in the Workroom Environment with Intended
Changes for 1977. Cincinnati: American Conference of
Governmental Industrial Hygienists, 1977.

10. American Public Health Association Intersociety Committee.
Methods of Air Sampling and Analysis. Washington, D.C.:
American Public Health Association, Inc., 1972. 480 pp.

11. Andersen, I., G. R. Lundqvist, and L. Mgflhave. Formaldehyde in
the atmosphere in Danish homes. Ugeskr. Laeg. 136:2133-2139,
1974. (in Danish; Eng. summary)

12. Bailey, B. W. , and J. M. Rank in. New spec trophotome trie method
for determination of formaldehyde. Anal. Chem. 43:782-784, 1971

13. Barber, E. D. , and J. p. Lodge, Jr. Paper chroma tographic
identification of carbonyl compounds as their

2,4-dinitro-phenylhydrazones in automobile exhaust. Anal. Chem,
35:348-350, 1963.

14. Battigelli, M. C. Sulfur dioxide and acute effects of air
pollution. J. Occup. Med. 10:500-511, 1968.

15. Becker, K. H., U. Schurath, and T. Tatarczyk. Fluorescence
determination of low formaldehyde concentrations in air by dye
laser excitation. Appl. Opt. 14:310-313, 1975.

16. Bell, R. P. The reversible hydration of carbonyl compounds.
Advan. Phys. Org. Chem. 4:1-29, 1966.

17. Bell, R. P., and P. G. Evans. Kinetics of the dehydration of
methylene glycol in aqueous solution. Proc. Roy. Soc., Series
291:297-323, 1966.

18. Bellar , T. A., and J. E. Sigsby, Jr. Direct gas chroma tog raphi
analysis of low molecular weight substituted organic compounds
in emissions. Environ. Sci. Technol. 4:150-156, 1970.

19. Belman, S. The fluorimetric determination of formaldehyde.
Anal. Chim. Acta 29:120-126, 1963.

20. Berge, A., and B. Mellegaard. Formaldehyde emission from
particleboard A new method for determination. For. Prod. J.
29(l):21-25, 1979.

21. Blejer, H. P., and B. H. Miller. Occupational Health Report of
Formaldehyde Concentrations and Effects on Workers at the Bayly
Manufacturing Company, Visalia. Study Report No. S-1806. Los
Angeles: State of California Health and Welfare Agency,
Department of Public Health, Bureau of Occupational Health,
1966. 6 pp.

22. Bowmer, K. H., A. R. G. Lang, M. L. Higgins, A. R. Pillay, and
Y. T- Tchan. Loss of acrolein from water by volatilization and
degradation. Weed Res. 14:325-328, 1974.

23. Braddock, R. J. f and J. W. Kesterson. Quantitative analysis of
aldehydes, esters, alcohols and acids from citrus oils. J. Foe
Sci. 41:1007-1010, 1976.

166

24. Breysse/ P. A. The environmental problems of urea-formaldehyde
structures formaldehyde exposure in mobile homes. Presented at
the American Medical Association Congress on Occupational
Health, October 26, 1979.

25. Bricker, C. E. , and H. R. Johnson. Spectrophotometric method
for determining formaldehyde. Ind. Eng. Chem., Anal. Ed.
17:400-40*2, 1945.

26. Campbell, E. E. , G. 0. Wood, and R. G. Anderson. Development of
Air Sampling Techniques LASL Project No. R-059. Quarterly
Report. September 16 - December 31, 1972. Los Alamos
Scientific Laboratory Report LA-5164-PR. Los Alamos, New
Mexico: Atomic Energy Commission, 1973. 6 pp.

27. Cantor, T. R. Experience with the determination of atmospheric
aldehydes, pp. 514-515. In Automation in Analytical Chemistry.
Technicon Symposia 1966. Vol. I. White Plains: Mediad, 1967.

28. Cares, J. W. Determination of formaldehyde by the chromatropic
acid method in the presence of oxides of nitrogen. Am. Ind.
Hyg. Assoc. J. 29:405-410, 1968.

29. Carey, M. A., and H. E. Persinger. Liquid chroma tographic
determination of derivatives that contain the dinitrophenyl
group. J. Chromat. Sci. 10:537-543, 1972.

30. Chrastil, J., and J. T. Wilson. A sensitive colorimetric method
for formaldehyde. Anal. Biochem. 63:202-207, 1975.

31. Cohen, I. R. , and A. P. Altshuller. A new Spectrophotometric
method for the determination of acrolein in combustion gases and
in the atmosphere. Anal. Chem. 33:726-733, 1961.

32. Colket, M. B., D. W. Naegeli, F. L. Dryer, and I. Glassman.
Flame ionization detection of carbon oxides and hydrocarbon
oxygenates. Environ. Sci. Technol. 8:43-46, 1974.

33. Cotton, F. A., and G. Wilkinson. Advanced Inorganic Chemistry:
A Comprehensive Text. 3rd ed. New York: John Wiley & Sons,
Inc., 1972. 1145 pp.

34. Dagani, D. , and M. C. Archer. Colorimetric determination of
actaldehyde in the presence of formaldehyde. Anal. Biochem.
87:455-459, 1978.

35. Dickinson, R. G., and N. W. Jacobsen. A new sensitive and
specific test for the detection of aldehydes: Formation of
6-mercapto-3-substituted-s-triazolo[4,3-b] -s-tetrazines. Chem.
Commun. 24:1719-1720, 1970.

36. Driscoll, J. N. Evaluation of a new photoionization detector
for organic compounds. J. Chromat. 134:49-55, 1977.

37. Eegriwe, E. Reactions and reagents for the detection of organic
compounds. Z. anal. Chem. 110:22025, 1937.

38. Elliott, M. A., G. J. Nebel, and F. G. Rounds. The composition
of exhaust gases from diesel, gasoline and propane powered motor
coaches. J. Air Pollut. Control Assoc. 5:103-108, 1955.

39. Ellis, C. F. Chemical Analyses of Automobile Exhaust Gases for
Oxygenates. U.S. Bureau of Mines Report of Investigations
5822. Pittsburgh: U.S. Department of the Interior, Bureau of
Mines, 1961. 35 pp.

167

40. Ellis, C. F. , R. F. Kendall, and B. H. Eccleston.
Identification of some oxygenates in automobile exhausts by
combined gas liquid chromatography and infrared techniques.
Anal. Chem. 37:511-516, 1965.

41. Flath, R. A., D. R. Black, D. G. Guadagni, W. H. McFadden, and
T. H. Schultz. Identification and organoleptic evaluation of
compounds in Delicious apple essence. J. Agric. Food Chem.
15:29-35, 1967.

42. Fracchia, M. F., F. J. Schuette, and P. K. Mueller. A method
for sampling and determination of organic carbonyl compounds in
automobile exhaust. Environ. Sci. Technol. 1:915-922, 1967.

43. Freed, D. J., and A. M. Mujsce. In situ generation of standards
for gas chroma tographic analysis. Anal. Chem. 49:139-141, 1977.

44. Freeman, H. G. , and W. C. Grendon. Formaldehyde detection and
control in the wood industry. For. Prod. J. 21(9):54-57, 1971.

45. Gadbois, D. F. , J. M. Mendelsohn, and L. J. Ronsivalli.
Modification of Girard-T reagent method for concentrating
carbonyl compounds for gas chromatographic analysis. Anal.
Chem. 37: 1776-1778, 1965.

46. Gadbois, D. F. , P. G. Scheurer, and F. J. King. Analysis of
saturated aldehydes by gas-liquid chromatography using
methylolphthalimide for regeneration of their Girard-T
derivatives. Anal. Chem. 40:1362-1365, 1968.

47. Garry, V. F. , L. Oatman, R. Pleus, and D. Gray. Formaldehyde in
the home. Some environmental disease perspectives. Minn. Med.
63:107-111, 1980.

48. Gold, A., C. E. Dub6, and R. B. Perni. Solid sorbent for
sampling acrolein in air. Anal. Chem. 50:1839-1841, 1978.

49. Gronsberg, E. S. Determination of acrolein and vinyl butyl
ether in the atmosphere. Gig. Truda Prof. Zabol. 12 (7): 54-56,
1968. (in Russian)

50. Halvarson, H. Quantitative gas chromatographic analysis of
micro amounts of volatile carbonyl compounds via their DNPH
derivatives. J. Chromat. 57:406-409, 1971.

51. Halvarson, H. The qualitative and quantitative evaluation of
the low-molecular-weight monocarbonyls in meat products. J.
Chromat. 66:35-42, 1972.

52. Harrenstein, M. S. Measurements of Aldehyde Concentrations in
the Exhaust of an Internal Combustion Engine Fueled by
Alcohol/Gasoline Blends. Graduate Thesis H296M. Coral Gables,
Fla.: University of Miami, 1978. 99 pp.

53. Hauser, T. R. , and R. L. Cummins. Increasing sensitivity of
3-methyl-2-benzothiazolone hydrazone test for analysis of
aliphatic aldehydes in air. Anal. Chem. 36: 679-681, 1964.

54. Hemenway, D. R. , M. C. Costanza, and S. M. MacAskill. Review of
the 4-hexylresorcinol procedure for acrolein analysis. Am. Ind.
Hyg. Assoc. J. 41:305-308, 1980.

55. Hoshika, Y., and Y. Takata. Gas chromatographic separation of
carbonyl compounds as their 2,4-dinitrophenylhydrazones using
glass capillary columns. J. Chromat. 120:379-389, 1976.

168

56. Howe, L. H. Differential pulse polarographic determination of
acrolein in water samples. Anal. Chem. 48:2167-2169, 1976.

57. Hrubesh, L. W. Microwave rotational spectroscopy. Technique
for specific pollutant monitoring. Radio Sci. 8:167-175, 1973.

58. Hrubesh, L. W., A. S. Maddux, D. C. Johnson, R. L. Morrison, J.
N. Nielson, and M. Malachosky. Portable microwave multi-gas
analyzer development. Lawrence Livermore Laboratory Report No.
UCID-17867. Livermore, Cal.: University of California,
Lawrence Livermore Laboratory, 1978. 110 pp.

59. Hughes, K. J., and R. W. Hurn. A preliminary survey of
hydrocarbon-derived oxygenated material in automobile exhaust
gases. J. Air Poll. Contr. Assoc. 10:367-373, 1960.

60. Hughes, K. J., R. W. Hurn, and F. G. Edwards. Separation and
identification of oxygenated hydrocarbons in combustion products
from automotive engines. Gas Chromat., Proc. 2nd Int. Symp.,
East Lansing, Michigan, 1959. Pp. 171-182, 1961.

61. Ikeda, S. Rapid determination of formaldehyde by short-circuit
argentometric amperometric titration using a rotating platinum
microelectrode. Anal. Chem. 46:1587-1588, 1974.

62. Jacobsen, N. W. , and R. G. Dickinson. Spectrometric assay of
aldehydes as 6-mercapto-3-substituted-s_-tnazolo(4,3-b)-
-tetrazines. Anal. Chem. 46:298-299, 1974.

63. Johnson, C. B. , A. M. Pearson, and L. R. Dugan, Jr. Gas
chromatographic analysis of the dimethylhydrazones of long chain
aldehydes. Lipids 5:958-963, 1970.

64. Johnson, D. C., and E. G. Hammond. A sensitive method for the
determination of carbonyl compounds. J. Am. Oil Chem. Soc.
48:653-656, 1971.

65. Jones, L. A., and R. J. Monroe. Flash exchange method for
quantitative gas chromatographic analysis of aliphatic carbonyls
from their 2,4-dinitrophenylhydrazones. Anal. Chem. 37:935-938,
1965.

66. Kadaba, P. K., P. R. Bhagat, and G. N. Goldberger. Application
of microwave spectroscopy for simultaneous detection of toxic
constituents in tobacco smoke. Bull. Environ. Contain. Toxicol.
19:104-112, 1978.

67. Kallio, H., R. R. Linko, and J. Kaitaranta. Gas-liquid
chromatographic analysis of 2,4-dinitrophenylhydrazones of
carbonyl compounds. J. Chromat. 65:355-360, 1972.

68. Katz, M. , Ed. Methods of Air Sampling and Analysis. 2nd ed.
Washington, D. C.: American Public Health Association, 1977.
984 pp.

69. Kerfoot, E. J., and T. F. Mooney, Jr. Formaldehyde and
paraformaldehyde study in funeral homes. Am. Ind. Hyg. Assoc.
J. 36:533-537, 1975.

70. Kissel, C. L., J. L. Brady, A. M. Guerra, J. K. Pau, B. A.
Rockie, and F. F. Caserio, Jr. Analysis of acrolein in aged
aqueous media. Comparison of various analytical methods with
bioassays. J. Agric. Food Chem. 26:1338-1343, 1978.

169

71. Korolczuk, J. f M. Daniewski, and Z. Mielniczuk. Gas
chromatographic determination of carbonyl compounds as their
phenylhydrazones . J. Chromat. 88:177-182, 1974.

72. Krug, E. L. R. , and W. E. Hirt. Interference of nitrate in the
determination of formaldehyde by the chromotropic acid method.
Anal. Chem. 49:1865-1867, 1977.

73. Lahmann, E., and K. Jander. Formaldehyd-Bestimmungen in
Strassenluft. Gesundherts-Ingenieur . 89:18-21, 1968.

74. Larson, G. P., P. P. Mader, P. H. Ziets, and E. E. McMahon.
Quantitative determination of aldehyde, pp. 31-37. In Test
Procedures and Methods in Air Pollution Control. Los Angeles:
Air Pollution Control District, County of Los Angeles, 1950. 60
pp.

75. Leach, P. W., L. J. Leng, T. A. Bellar, J. E. Sigsby, Jr., and
A. P. Altshuller. Effects of HC/NO X ratios on irradiated auto
exhaust. Part II. J. Air Pollut. Control Assoc. 14:176-183,
1964.

76. Ledbury, W. , and E. W. Blair. The partial formaldehyde vapour
pressures of aqueous solutions of formaldehyde. Part II. J.
Chem. Soc. 127:2832-2839, 1925.

77. Levaggi, D. A., and M. Feldstein. The collection and analysis
of low molecular weight carbonyl compounds from source
effluents. J. Air Pollut. Control Assoc. 19:43-45, 1969.

78. Levaggi, D. A., and M. Feldstein. The determination of
formaldehyde, acrolein, and low molecular weight aldehydes in
industrial emissions on a single collection sample. J. Air
Pollut. Control Assoc. 20:312-313, 1970.

79. Lin, C.-I., R. N. Anaclerio, D. W. Anthon, L. Z. Fanning, and C.
D. Hollowell. Indoor /outdoor measurements of formaldehyde and
total aldehydes. Presented at the 178th National American
Chemical Society Meeting, Washington, D.C., September 9-14,
1979. 11 pp.

80. Linko, R. R. , H. Rallio, and K. Rainio. Gas-liquid
chromatographic analysis of 2,4,-dinitrophenylhydrazones of
monocarbonyl compounds in carrots using glass capillary
columns. J. Chromat. 155:191-194, 1978.

81. Linnell, R. H., and W. E. Scott. Diesel exhaust analysis.
Preliminary results. Arch. Environ. Health 5:616-625, 1962.

82. Linnell, R. H., and W. E. Scott. Diesel exhaust composition and
odor studies. J. Air Pollut. Control Assoc. 12:510-515, 545,
1962.

83. Lupton, J. M., and C. C. Lynch. Polarographic examination of
carbonyl compounds. J. Am. Chem. Soc. 66:697-700, 1944.

84. Lyles, G. R. , F. B. Dowling, and V. J. Blanchard. Quantitative
determination of formaldehyde in the parts per hundred million
concentration level. J. Air Pollut. Control Assoc. 15:106-108,
1965.

85. Major, R. T., P. Marchini, and A. J. Boulton. Observation on
the production of ot-hexenal by leaves of certain plants. J.
Biol. Chem. 238:1813, 1963.

170

86. Major, R. T., and M. Thomas. Formation of 2-hexenal from
linolenic acid by macerated Ginkgo leaves. Phytochem.
11:611-617, 1972.

87. Mansfield, C. T., B. T. Hodge, R. B. Hege, Jr., and W. C.
Hamlin. Analysis of formaldehyde in tobacco smoke by high
performance liquid chroma tography. J. Chromat. Sci. 15:301-302,
1977.

88. Mari, R., M. Feve, and M. Dzierzinsky. Colorimetric reaction
between phenylhydrazine, formaldehyde, and oxygen in alkaline
solution. Determination of formaldehyde. Bull. Soc. Chim.
France 1961: 1395-1399, 1961.

89. McLean, J. D., and J. F. Holland. Development of a portable
polarograph for determination of aldehydes in automotive exhaust
and production plant samples. Environ. Sci. Technol. 9:127-131,
1975.

90. Meyer, B. Urea-Formaldehyde Resins, p. 128. Reading, Mass.:
Add i son -Wesley Publishing Company, 1979.

91. Miller, B. H., and H. P. Blejer. Report of an Occupational
Health Study of Formaldehyde Concentrations at Maximes, 400 E.
Colorado Street, Pasadena, California. Study No. S-1838. Los
Angeles: State of California Health and Welfare Agency,
Department of Public Health, Bureau of Occupational Health,
1966. 5 pp.

92. Morgan, G. B., C. Golden, and E. C. Tabor, new and improved
procedures for gas sampling and analysis in the National Air
Sampling Network. J. Air Pollut. Control Assoc. 17:300-304,
1967.

93. Moschandreas, D. J., J. W. C. Stark, J. E. McFadden, and S. S.
Morse. Indoor Air Pollution in the Residential Environment.
Vol. 1. Data Collection, Analysis and Interpretation. U.S.
Environmental Protection Agency Report No. EPA 600/7-78-229a.
Research Triangle Park, N.C.: U.S. Environmental protection
Agency, Office of Research and Development, Environmental
Monitoring and Support Laboratory, 1978. 201 pp.

94. Nash, T. Colorimetric estimation of formaldehyde by means of
the Hantzsch reaction. Biochem. J. 55:416-421, 1953.

95. Nauman, R. V., P. W. West, F. Tron, and G. C. Gaeke, Jr. A
spectrophotometric study of the Schiff reaction as applied to
the quantitative determination of sulfur dioxide. Anal. Chem.
32:1307-1311, 1960.

96. Olansky, A. S., and S. N. Deming. Optimization and
interpretation of absorbance response in the determination of
formaldehyde with chromotropic acid. Anal. Chim. Acta 83:
241-249, 1976.

97. Osman, S. F., and J. L. Barson. Solvent f ractionation of Girard
T derivatives of carbonyl compounds using dimethyl sulf oxide.
Anal. Chem. 39:530-531, 1967.

98. Pagnotto, L. D. Gas and vapor sample collectors, pp. R1-R18.
In Air Sampling Instruments for Evaluation of Atmospheric
Contaminants. 5th ed. Cincinnati: American Conference of
Governmental Industrial Hygienists, 1978.

171

99. Palmes, E. D. , A. F. Gunnison, J. DiMattio, and C. Tomczyk.
Personal sampler for nitrogen dioxide. Am. ind. Hyg. Assoc. J.
37:570-577, 1976.

100. Papa, L. J. Color ime trie determination of carbonyl compounds in
automotive exhaust as 2,4-dinitrophenylhydrazones. Environ.
Sci. Technol. 3:397-398, 1969.

101. Papa, L. J., and L. P. Turner. Chromatographic determination of
carbonyl compounds as their 2,4-dinitrophenylhydrazones. I. Gas
chroma tog raphy. J. Chromat. Sci. 10: 744-747, 1972.

102. Papa, L. J., and L. P. Turner. Chromatographic determination of
carbonyl compounds as their 2,4-dinitrophenylhydrazones. II.
High pressure liquid chroma tog raphy. J. Chromat. Sci. 10:
747-750, 1972.

103. Pellizzari, E. D. Development of Analytical Techniques for
Measuring Ambient Atmospheric Carcinogenic Vapors. U.S.
Environmental Protection Agency Report No. EPA-600/2-75-076.
Research Triangle Park, N.C.: U.S. Environmental Protection
Agency, Office of Research and Development, Environmental
Sciences Research Laboratory, 1975. 201 pp.

104. Pellizzari, E. D. Development of Method for Carcinogenic Vapor
Analysis in Ambient Atmospheres. U.S. Environmental Protection
Agency Report No. EPA-650/2-74-121. Research Triangle Park,
N.C.: U.S. Environmental Protection Agency, Office of Research
and Development, National Environmental Research Center,
Chemistry and Physics Laboratory, 1974. 148 pp.

105. Pinigina, I. A. Use of 2,4-dinitrophenylhydrazine for
determining carbonyl compounds in the air. Gig. Sanit.
37(4):78-81, 1972. (in Russian)

106. Pressman, D. , and H. J. Lucas. Hydration of unsaturated
compounds. XI. Acrolein and acrylic acid. J. Am. Chem. Soc.
64:1953-1957, 1942.

107. Pyne. A. W. , and E. L. Wick. Volatile components of tomato. J.
Food Sci. 30:192-200, 1965.

108. Radian Corporation. Houston Area Oxidants Study. Report No.
HCP-6. Austin, Texas: Radian Corporation, 1977.

109. Rails, J. W. Higher recoveries of carbonyl compounds in flash
exchange gas chroma tog raphy of 2,4-dinitrophenylhydrazones.
Anal. Chem. 36:946, 1964.

110. Rayner, A. C., and C. M. Jephcott. Microdetermination of
formaldehyde in air. Anal. Chem. 33:627-630, 1961.

111. Reckner, L. R. , W.E. Scott, and W. F. Biller. The composition
and odor of diesel exhaust. Proc. Am. Petrol. Inst. 45:
133-147, 1965.

112. Renzetti, N. A., and R. J. Bryan. Atmospheric sampling for
aldehydes and eye irritation in Los Angeles smog 1960. J. Air
Pollut. Control Assoc. 11:421-424, 427, 1961.

113. Roffael, E. Formaldehyde Release from Particleboard Methods of
Determination. Presented at the Consumer Product Safety
Commission Technical Workshop on Formaldehyde, Washington, D.C. ,
April 1980.

172

114. Sawicki, E. f and R. A. Carnes. Spectrophotofluorimetric
determination of aldehydes with dimedone and other reagents.
Mikrochim. Acta 1968:148-159, 1968.

115. Sawicki, E., and T. R. Hauser. Spot test detection and
color imetric determination of aliphatic aldehydes with
2-hydrazinobenzothiazole. Application to air pollution. Anal.
Chem. 32:1434-1436, 1960.

116. Sawicki, E., T. R. Hauser, and S. McPherson. Spectrophotometric
determination of formaldehyde and formaldehyde-releasing
compounds with chromotropic acid, 6-amino-l-naphthol-3-sulfonic
acid (J acid) , and 6-anilino-l-naphthol-3-sulfonic acid (phenyl
J acid). Anal. Chem. 34:1460-1464, 1962.

117. Sawicki, E. , T. R. Hauser, T. W. Stanley, and W. Elbert. The
3-methyl-2-benzothiazolone hydrazone test. Sensitive new methods
for the detection, rapid estimation, and determination of
aliphatic aldehydes. Anal. Chem. 33:93-96, 1961.

118. Sawicki, E., T. W. Stanley, and J. Pfaff. Spectrophoto-
fluorimetric determination of formaldehyde and acrolein with J
acid. Comparison with other methods. Anal. Chim. Acta
28:156-163, 1963.

119. Scaringelli, F. P., A. E. O'Keefe, E. Rosenberg, and J. p.
Bell. Preparation of known concentrations of gases and vapors
with permeation devices calibrated gravimetrically. Anal. Chem.
42:871-876, 1970.

120. Schiff, H. Eine neue Reithe organisher Diamine. Ann. Chem.
140:92, 1866. (in German)

121. Schuck, E. A., E. R. Stephens, and J. T. Middleton. Eye
irritation response at low concentrations of irritants. Arch.
Environ. Health 13:570-575, 1966.

122. Schuette, F. J. Plastic bags for collection of gas samples.
Atmos. Environ. 1:515-519, 1967.

123. Scott Research Laboratories, Inc. Atmospheric Reaction Studies
in the Los Angeles Basin. Phase I. Vol. II. Washington, B.C.:
U.S. Public Health Service, National Air Pollution Control
Administration, 1969. 542 pp.

124. Seizinger, D. E., and B. Dimitriades. Oxygenates in Automotive
Exhaust Gas. Estimation of Levels of Carbonyls and Noncarbonyls
in Exhaust from Gasoline Fuels. Bureau of Mines Report of
Investigations 7675. Bartlesville, Okla.: U.S. Bureau of
Mines, 1972. 75 pp.

125. Seizinger, D. E., and B. Dimitriades. Oxygenates in Automotive
Exhausts. Effect of an Oxidation Catalyst. Bureau of Mines
Report of Investigations 7837. Bartlesville, Okla.: U.S.
Bureau of Mines, 1973. 26 pp.

126. Selim, S. Separation and quantitative determination of traces
of carbonyl compounds as their 2,4-dinitrophenylhydrazones by
high pressure liquid chromatography. J. Chromat. 136:271-277,
1977.

127. Shipkovitz, H. D. Formaldehyde Vapor Emissions in the
Permanent-Press Fabric Industry. Report No. TR-52. Cincinnati:
U.S. Department of Health, Education, and Welfare, Public Health

173

Service, Consumer Protection and Environmental Health Service,
Environmental Control Administration, September 1968. 18 pp.

128. Slawinska, D. , and J. Slawinski. Chemiluminescent flow method
for determination of formaldehyde. Anal. Chem. 47:2101-2109,
1975.

129. Sleva, S. F. Determination of formaldehyde-chromotropic acid
method, pp. H-l H-5. In Interbranch Chemical Advisory Group.
Selected Methods for the Measurement of Air Pollutants. DREW
(PHS) Publication No. 999-AP:ll. Washington, D.C.: U.S.
Government Printing Office, 1965.

130. Smith, C. W. , Ed. Acrolein. Heidelberg, Germany: Huethig,
1975. (in German; English abstract in Chem. Abstr. 87: 102823 j,
1977)

131. Soukup, R. J., R. J. Scarpellino, and E. Danielczik. Gas
chromatographic separation of 2,4-dinitrophenylhydrazone
derivatives of carbonyl compounds. Anal. Chem. 36:2255-2256,
1964.

132. Stevens, K. L. , J. L. Bomben, and W. H. McFadden. Volatiles
from grapes. Vitis vinifera (Linn) cultivar Grenache. J. Agric.
Food Chem. 15:378-380, 1967.

133. Szelejewska, I. Spectrophotometric determination of
formaldehyde in presence of acrolein. Chem. Anal. (Warsaw)
20:325-330, 1975. (in Polish; English summary)

134. Tanebaum, M. , and C. E. Bricker. Microdetermination of free
formaldehyde. Anal. Chem. 23:354-357, 1951.

135. Teranishi, R. , J. W. Corse. W. H. McFadden, D. R. Black, and A.
I. Morgan, Jr. Volatiles from strawberries. I. Mass spectral
identification of the more volatile compounds. J. Food Sci.
28:478-483, 1963.

136. Tsang, W. , and J. A. Walker. Instrument for the generation of
reactive gases. Anal. Chem. 49:13-17, 1977.

137. Tuazon, E. C., R. A. Graham, A.M. Winer, R. R. Easton, J. N.
Pitts, Jr., and P. L. Hanst. A kilometer pathlength
Fourier-transform infrared system for the study of trace
pollutants in ambient and synthetic atmospheres. Atmos.
Environ. 12:865-875, 1978.

138. U.S. Department of Health, Education, and Welfare, Public Health
Service, National Institute for Occupational Safety and Health.
Criteria for a Recommended Standard. . .Occupational Exposure to
Formaldehyde. DHEW (NIOSH) Publication No. 77-126. Washington,
D.C.: U.S. Government Printing Office, 1976. 165 pp.

139. U.S. Department of Health, Education, and Welfare, Public Health
Service, National Institute for Occupational Safety and Health.
Manual of Analytical Methods, pp. 125-1--125-9. 2nd ed. Vol.

1. Washington, D.C.: U.S. Government Printing Office, 1973.

140. U.S. Department of Labor, Occupational Safety and Health
Administration. Safety and health regulations for construction.
Recodification of air contaminant standards. Fed. Reg.
40:23072-23073, 28 May 1975.

141. Vogh, J. W. Isolation and analysis of carbonyl compounds as
oximes. Anal. Chem. 43:1618-1623, 1971.

174

142. Walker, J. F. Formaldehyde. 3rd ed. Huntington, N.Y.: Robert
E. Krieger Publishing Co., 1975. 728 pp.

143. West, P. W. r and G. C. Gaeke. Fixation of sulfur dioxide as
disulfitomercurate (II) and subsequent color imetric estimation.
Anal. Chem. 28:1816-1819, 1956.

144. West, P. W. , and T. P. Ramachandran . Spectrophotometric
determination of nitrate using chromotropic acid. Anal. Chim.
Acta 35:317-324, 1966.

145. West, P. W. , and B. Z. Sen. Spectrophotometric determination of
traces of formaldehyde. Z. anal. Chem. 153:177-183, 1956.

146. Wilson, K. W. Fixation of atmospheric carbonyl compounds by
sodium bisulfite. Anal. Chem. 30:1127-1129, 1958.

147. Winter, M. , and E. Sundt. Flavors. V. Analysis of the
raspberry flavoring material. 1. Volatile carbonyl
constituents. Helv. Chim. Acta 45:2195-2211, 1962. (in French)

148. World Health Organization Working Group. Health Aspects Related
to Indoor Air Quality. Report on a WHO Working Group.
Copenhagen, Denmark: World Health Organization, 1979. 34 pp.

149. Yamate, N., and T. Matsumura. Determination of acrolein in
ambient air by square wave polarography. Eisei Shikenjo Hokoku

(Japan) 93:130-132, 1975. (in Japanese; English abstract in
Chem. Abstr. 85:129642v, 1975)

150. Yunghans, R. S., and W. A. Munroe. Continuous monitoring of
ambient atmospheres with the Technicon AutoAnalyzer , pp.
279-284. In Automation in Analytical Chemistry. Technicon
Symposia 1965. Vol. 1. White Plains, New York: Mediad Inc.,
1966.

CHAPTER 7
HEALTH EFFECTS OF FORMALDEHYDE

There is an increasing body of evidence that the exposure of the
human population to formaldehyde vapors may be the source of the many
complaints related to irritation of the eyes and respiratory tract,
headache, tiredness, and thirst; these symptoms have been reported by
occupants of homes, schools, and industrial buildings mainly by
residents of homes in which formaldehyde has been detected at high
concentrations. Owing to the common use of formaldehyde in building
materials and in foam insulation, there is a potential for exposure of
employees engaged in the manufacture of these products and for
exposure of the general public using the products. Furthermore, there
are many workers in a great variety of occupations who, through the
use of formaldehyde and its associated products, may be exposed to
formaldehyde at high concentrations in the course of a day's work (see
Table 7-1) . Energy-conservation measures that have become widely used
in recent years, including reduced ventilation rates, have led to
increased indoor formaldehyde concentrations .2126 We have
considered in some detail (in Chapter 5) these and the many other
sources of formaldehyde pollution in our environment today. In view
of the widespread use of formaldehyde and the large number of people
who are exposed to it, we must be concerned about the potential health
effects associated with these exposures.

Because of the unique importance of formaldehyde among the many
aldehydes in use today, we devote this chapter to its consideration.
The health effects of the several other important aldehydes are
discussed in Chapter 8. Eye irritation and respiratory tract
irritation are common results of human exposure to formaldehyde at
relatively low concentrations. Documented cases of hypersensitivity
with bronchial asthma due specifically to formaldehyde are few; more
commonly, asthma is aggravated by the irritating properties of
formaldehyde. Aqueous solutions damage the eye and irritate the skin
on direct contact. Repeated exposure to dilute solutions may lead to
allergic contact dermatitis. Systemic formaldehyde poisoning by
ingestion is uncommon, because its irritancy makes ingest ion
unlikely. We discuss here the preliminary findings of a Chemical
Industry Institute of Toxicology (CUT) study with regard to
formaldehyde induction of nasal cancer in rats and mice. The human
carcinogenic, mutagenic, and teratogenic potential of formaldehyde is

175

176

TABLE 7-1
Potential Occupational Exposures to Formaldehyde 2

Anatomists
Agricultural workers

Bakers

Beauticians

Biologists

Bookbinders

Botanists

Crease-resistant-textile

finishers
Concrete users

Dentists

Deodorant makers

Dialysis technicians

Disinfectant makers

Disinfectors

Dress-goods store personnel

Dressmakers

Drugmakers

Dry cleaners

Dyemakers

Electric-insulation makers
Emb aimers

Embalmin-fluid makers
Ethylene glycol makers

Fertilizer makers
Fireproofers

Formaldehyde-resin makers
Formaldehyde workers
Fumlgators
Fungicide workers
Furniture dippers and sprayers
Fur processors

Glass etchers

Glue and adhesive makers

Hexamethylenetetramine makers
Hide preservers
Histology technicians
Home construction workers

Ink makers

Lacquerers and lacquer makers
Laundry workers

Medical personnel
Mirror workers

Oil-well workers

Paper makers
Pentaerythritol makers
Photographic-film makers

Resin makers
Rubber makers

Soil sterilizers and green-
house workers
Surgeons

Tannery workers

Taxidermists

Textile mordanters and printers

Textile waterproofers

Varnish workers
Wood preservers

Modified from NIOSH. 198

177

not known, but it has exhibited mutagenic activity in a wide variety
of organisms.

ASSESSMENT OF ADVERSE HEALTH EFFECTS

Adverse health effects due to formaldehyde may occur after
exposure by inhalation, ingestion, or skin contact. It is difficult
to ascribe specific health effects to specific concentrations of
formaldehyde to which people are exposed, because they vary in their
subjective responses and complaints. Moreover, persons with disease
may be more responsive to low concentrations than hyposensitive
persons who do not respond to the same concentrations. Thus, the
threshold for response will not be constant among all segments of the
population. Also, studies done in homes, both mobile and
conventional, where the subjective complaints of consumers reportedly
can be ascribed to formaldehyde (especially when only formaldehyde is
measured) may not be completely valid, because other pollutants acting
independently may cause the same symptoms or synergistically may
enhance the perception of symptoms. (See Chapter 5 for factors that
affect the outgassing of formaldehyde.) Interpretation of the health
effects of formaldehyde must consider not only the concentration, but
also the duration of exposure of subjects. For example, in some
studies, exposures lasted only a few minutes; 81 90 132 17S 207 in
others, they lasted several hours 72 137 179 183 or days. 215 2l7 A
short-term inhalation study cannot accurately predict the effects of
formaldehyde on persons who reside in homes where there is a
continuous low-dose exposure. Tolerance may develop after several
hours of exposure 15 loz 173 and modify the response to
formaldehyde. In some persons not previously sensitized, repeated
exposure to formaldehyde may result in the development of
hyper sensitivity.

Analytical procedures for formaldehyde vary in both sensitivity
and specificity (see Chapter 6) . * 29 31 as ss 82 us ne 136 isa

158 159 166 177 178 186 216

BIOCHEMISTRY AND METABOLISM OF FORMALDEHYDE

Formaldehyde is a normal metabolite and a vital ingredient in the
synthesis of essential biochemical substances in man and thus in small
quantities is not toxic. 39 109 Formaldehyde controls a
rate-limiting step in the processing of methyl groups derived from the
metabolic dealkylation of O-, N-, and S_-methyl compounds during their
detoxification and excretion. 209 With ample dietary supplies of
tetrahydrofolic acid, vitamin B-j^ r and such sulfhydryl compounds as
cysteine and methionine, small amounts of formaldehyde are readily
metabolized.

Formaldehyde also is involved in lipid metabolism in the
decomposition of peroxides by catalase. 203

178

The biochemical transformations of endogenous and exogenous
formaldehyde are similar and involve coenzymes and hydrogen transport
systems that are normally present in all animals and bacteria. 39 " 109
Interspecies variations in the metabolism of formaldehyde may account
for differences in reaction rates in these systems. 55 75 7 205 209
Formaldehyde oxidation, for example, is greater in human liver than in
rat liver; this may explain the unique susceptibility of man to
methanol poisoning. 18S

The main reaction of formaldehyde appears to be an initial
oxidation to formic acid in the liver and erythrocytes. 39 5S " 103 109 12t
Once formic acid is formed, it can undergo three reactions: oxidation
to carbon dioxide and water, elimination in the urine as a sodium
salt, or entrance into the metabolic one-carbon pool. Formaldehyde
may also enter the one-carbon pool directly.

In man, the formation of formate from formaldehyde appears to
involve an initial reaction with glutathione to form a hemiacetal . 7 5 18I
The enzyme formaldehyde dehydrogenase (FDH) then oxidizes the
hemiacetal to formic acid, with NAD as a hydrogen acceptor. 55 18 *
In humans, FDH is a multifunctional complex of enzymes that converts
methanol to formic acid without releasing formaldehyde as an
intermediate, 75 18t| 202 206 inasmuch as it is difficult to isolate
FDH alone.

The molecular weight of human FDH is 81,400, and that of rats is
111, 000. 7S 20Z Human liver FDH activity is 50% greater than that of
rat liver, in terms of enzyme units per gram of liver. 75 The actual
product of the human FDH reaction is not free formic acid, but
-formylglutathione, which hydrolyzes slowly in human liver
preparations to formate. 202

Tran e_t al_. 191 investigated the uptake of [ 14 C] formaldehyde
and its conversion to carbon dioxide by erythrocytes from chronic
alcoholics and nonalcoholics. The ingestion of ethanol initially
decreased the rate of carbon dioxide production from formaldehyde in
both groups, but a greater decrease was noted in the alcoholics'
erythrocytes. A few hours later, the erythrocytes from alcoholics had
a carbon dioxide production rate well above their baseline values; the
rate returned to normal several days later. These findings could be
explained on the basis that ethanol interfered with tetrahydrofolic
acid activity during metabolism. The potential interference with
tetrahydrofolic acid activity brings up the theoretical possibility
that formaldehyde affects folate uptake by cells. Tetrahydrofolic
acid is important, in that an induced folate deficiency may result in
a number of medical conditions, including hematologic abnormalities
and neurologic and growth effects in infants. 12 17 121 12e 17 A
folate-dependent one-carbon pathway was found to be primarily
responsible for formate oxidation in monkeys poisoned with
methanol. 130 Formate elimination from the blood of folate-def icient
monkeys was about half that of controls.

It has been reported that formaldehyde causes the eye effects and
formic acid some of the acidosis seen in methanol poisoning. 33
Although in vitro studies indicate that formaldehyde has significant
effects on retinal oxidative phosphor ylat ions, l it is rapidly

179

metabolized to formic acid in humans, dogs, cats, rabbits, guinea
pigs, rats, and monkeys. 131 16 Formaldehyde is eliminated from the
blood with a half-life of 1-2 mm. in a study of formate-poisoned
monkeys, there was no detectable increase in formaldehyde
concentration in samples of blood, urine, cerebrospinal fluid,
vitreous humor, freeze-clamped liver (at the temperature of liquid
nitrogen), kidney, optic nerve, or brain, 12 " 131 at a time when
formate concentrations were high. In a recent report of methanol
poisoning in humans, formate accumulation was marked; that indicates
that formic acid plays a major role in the acidosis in human
poisonings. 12 9

Some adverse effects of formaldehyde may be related to its high
reactivity with amines and formation of methylol adducts with nucleic
acids, histones, proteins, and amino acids. The methylol adducts can
react further to form methylene linkages among these reactants. 11
118 It appears that before formaldehyde reacts with amino groups in
RNA, the hydrogen bonds forming the coiled RNA are broken. 61 * 1>tS
Formaldehyde reacts with DNA less frequently than with RNA, because
the hydrogen bonds holding DNA in its double helix are more stable. 6 "
172 Reaction of formaldehyde with DNA has been observed, by
spectrophotometry and electron microscopy, to result in irreversible
denaturation. In reactions with transfer RNA, formaldehyde interferes
with amino acid acceptance. 11 172 The equilibrium reaction of
formaldehyde with DNA involves thermally activated opening and closing
of hydrogen bonds between matching base pairs in the helix. 172 If
permanent cross links are formed between DNA reactive sites and
formaldehyde, these links could interfere with the replication of DNA
and may result in mutations. When human fetal lung fibroblasts were
incubated with tracer amounts of -^C-labeled formaldehyde and
acetaldehyde, l 55 a pulse of 10 rain with formaldehyde followed by a
6-min and 24-h chase showed migration of carbon-14 into the nucleus.
Fractionation of the nucleus revealed that the RNA fraction had the
highest absolute and specific activity, whereas the DNA and protein
fractions had considerably lower activity. All the counts from
formaldehyde were found in the adenine and guanine components of RNA.
The DNA count was distributed among adenine, guanine, and thymine.

EFFECTS IN ANIMALS
ACUTE TOXICOLOGY STUDIES

When administered orally, formaldehyde (formalin) is slightly

toxic in rats, with LDsp values reported in the range of 500-800
rag/kg. 179 193 When administered by inhalation, it is moderately
toxic in rats, with 3-min and 4-h LCsgS of 815 and 479 ppm,
respectively. 138 llfl Pulmonary edema was the predominant pathologic
change. Similar results were obtained in cats and mice.

Formaldehyde causes mild to moderate irritation when applied to
rabbit skin at 0.1-20% (Haskell Laboratory, Du Pont Company,
unpublished data) . Formaldehyde was also administered to nine guinea

180

pigs intradermally or topically over a 2-wk period. After a 2-wk rest
period, they were challenged with formaldehyde; five of the animals
had become sensitized. Dermal sensitization by airborne formaldehyde
has not been reported.

Formaldehyde is a severe eye irritant. Experimental application
of 0.005 ml of 15% formalin to rabbit eyes caused a severe
reaction corneal and conjunctival edema and iritis graded 8 on a
complex injury-grading scale of 1-10. 32 Exposure of rabbits to
formaldehyde vapors at 40-70 ppm caused slight tearing and eye
discharge, but not corneal injury. 78

EXTENDED TOXICOLOGY STUDIES

Continuous 90-d inhalation studies have been conducted with
several species of laboratory animals. In one study, rats, guinea
pigs, rabbits, monkeys, and dogs were exposed to formaldehyde at 3.7
ppm. 1 * One of the exposed rats died, but there were no overt signs
of toxicity. Various degrees of interstitial inflammation were seen
in the lungs of all the exposed animals, and there was focal chronic
inflammation in the hearts and kidneys of the rats and guinea pigs.
It was uncertain whether these changes were compound-related, in
another study, groups of 25 rats were continuously exposed at 1.6,
4.55, or 8.07 ppm for 45-90 d. 50 The only adverse effect at 1.6 ppm
was discoloration of the hair. The 4.55-ppm group was exposed for 45
d and had a decrease in rate of weight gain. The 8.07-ppm group was
exposed for 60 d and had respiratory and eye irritation, a decrease in
food consumption, and a decrease in liver weight.

In a noncontinuous inhalation study, groups of 20 mice and 20 rats
were exposed to formaldehyde at 4, 12.7, or 38.6 ppm, 6 h/d, 5 d/wk,
for 13 wk (Chemical Industry Institute of Technology, unpublished
data). No adverse effects were observed in the 4-ppm group. At 12.7
ppm, a decrease in body weight and evidence of nasal erosion in two
exposed rats were observed. Dlceration and necrosis of the nasal
mucosa seen at 38.6 ppm resulted in termination of exposure after 2
wk. Groups of 60 mice were exposed at 41 or 82 ppm, 1 h/d, three
times a week, for 35 wk." The 41-ppm group was then exposed at 123
ppm for 29 wk. All the groups tolerated the exposure reasonably well,
and the average weight of the mice rose normally. Pathologic
examination of the tracheal epithelium revealed basal cell
hyperplasia, squamous cell metaplasia, and atypical metaplasia.
Extension of metaplasia into the major bronchi was infrequent, except
in the animals that were exposed at 123 ppm. In these animals, the
metaplastic changes in the epithelium appeared to extend farther into
the major bronchi with increasing exposure. Exposure of a similar
group of mice at 163 ppm was terminated after 11 d, because of severe
pathologic changes and deaths.

The Formaldehyde Institute is sponsoring studies at Biodynamics,
Inc., on effects of virtually continuous inhalation of formaldehyde in
monkeys, hamsters, and rats. These are daily 22-h exposures at 3, 1,
and 0.2 ppm that are repeated for 26 wk. Results of gross and

181

microscopic evaluation of animals exposed at 0.2 and 1.0 ppm (now
completed) showed no treatment-related effects. Final results (C. F.
Reinhardt, personal communication) on animals exposed at 3 ppm have
shown no adverse effects in hamsters; in rats and monkeys, there is
histologic evidence of squamous metaplasia of the nasal mucosa in
exposed animals. The hamsters showed no histologic changes at any of
the exposure concentrations.

RESPIRATORY SYSTEM EFFECTS

Formaldehyde is readily soluble in the mucous membranes of
animals. Respiratory tract uptake is almost 100% in dogs. 52 When
inhaled by guinea pigs for 1 h at 0.3-50 ppm, formaldehyde increased
airway resistance and decreased compliance. These effects were
reversible at concentrations less than 40 ppm and were not seen 1 h
after exposure. Guinea pigs exposed for 1 h at 3.5 ppm had a 40%
increase in airflow resistance and a 12% decrease in compliance. The
increase in resistance was dose-related over the range of 0.25-50 ppm;
tracheal cannulation doubled the increase in resistance. The
combination of formaldehyde and sodium chloride aerosol (0.04 vim in
diameter) at 10 mg/m 3 further increased airway resistance. 6

In another study, 25 rats each were exposed continuously for 3 mo
at 0.0098, 0.028, 0.82, and 2.4 ppm. At 2.4 ppm, there was a
significant decrease in cholinesterase activity; at 2.4 and 0.82 ppm,
there were proliferation of lymphocytes and histiocytes in the lungs
and some peribronchial and perivascular hyper emia. There were no
significant findings at the two lower concentrations.

The effects of formaldehyde exposure on respiratory rate were
studied in mice. Exposure for 10 mm at 3.1 ppm, 3 h/d, for 3 d
before exposure at a higher challenge concentration (0.55-13.4 ppm)
produced the same response as in a previously un exposed group. Similar
exposure at concentrations higher than 3.1 ppm caused an increased
response. However, accommodation occurred during each exposure
period, with the respiration rate approaching normal. 98 Other
research has shown formaldehyde to decrease ciliary transport within
10 min at concentrations of 20-100 ppm. 1 * 2 * s

CARDIOVASCULAR SYSTEM EFFECTS

Large doses of formaldehyde have a vasopressor effect (increased
blood pressure) in anesthetized mice. Smaller doses lead to a
depressor response. Qualitatively, the responses are similar to that
seen with acetaldehyde. 53 Dogs do not have such responses to
formaldehyde. Other results from the same study suggest that an
initial decrease in blood pressure is caused by alterations in the
sympathetic nervous system. A later, more marked decrease may be the
result of a direct effect on vascular smooth muscle. 187

182
MUTAGENIC POTENTIAL

Numerous studies have been conducted to determine the mutagenicity
of formaldehyde, and Auerbach et^ al_. 1 1 have reviewed the subject
extensively. Formaldehyde has exhibited mutagenic activity in a wide
variety of organisms, but the mechanism of formaldehyde mutagenesis
has not been resolved. Formaldehyde may cause mutations by reacting
directly with DMA; by forming mutagenic products on reaction with
ami no groups on simple amines, ammo acids, nucleic acids, or
proteins; or by forming peroxides that can react directly with DNA or
indirectly by free-radical formation.

Mutagenic activity has been detected in E_. coli * * and
Pseudomonas fluorescens, s 8 but not in the Ames strains of Salmonella
typhimurium. 106 Sasaki and Endo reported that the mutagenicity of
formaldehyde was very weak and appeared only within a limited range of
concentration in which the Ames test was modified slightly by
preincubating for 15 min at 37C before charging the plates. 165
Weak mutagenic activity was observed when the fungi Neurospora crassa
and Aspergillus^ nidulans were treated. The increase in mutagenic
activity observed in these studies after treatment in the presence of
catalase inhibitors suggested that peroxides were involved in the
induction of mutations. Formaldehyde induced mitotic recombination in
Saccharomyces cerevisiae. 3I Recently, formaldehyde was shown to
induce mutations and cause DNA damage and repair in Saccharomyces. 35 117 lie
The studies concerning formaldehyde mutagenesis in Drosophila have
been reviewed by several authors. 11 l56 1B1 Mutations were induced
in male larvae fed formaldehyde-containing food and in adults given
injections of aqueous solutions of formaldehyde. The exposure of
adults or larvae to formaldehyde vapors has not produced mutations.
In one of five species of grasshoppers, formaldehyde caused
chromosomal damage. 120 Germinating barley seeds soaked in
formaldehyde solutions did not give evidence of mutations on
maturation. sl *

The mutagenic potential of formaldehyde in mammalian systems has
not been thoroughly studied. An increase in mutation frequency was
observed when formaldehyde was tested in the L5178Y mouse lymphoma
assay. 37 76 Formaldehyde increased the mutation frequency in each
of the four experiments conducted. However, a clear dose-response
relationship was evident in only one of four experiments. No mutagenic
activity was reported when formaldehyde was tested in the Chinese
hamster ovary cell/HGPRT assay. 93 The data and a description of the
treatment conditions have not yet been published. No effect was
observed in limited dominant-lethal studies in which Swiss mice were
given intraperitoneal injections of formaldehyde, 59 but many other
mutagens were inactive in this series of tests.

Formaldehyde has mutagenic activity in a variety of microorganisms
and in some insects. Work is necessary to ascertain its mutagenic
potential in in vitro cultures of germinal or somatic mammalian
cells. Such information would be used in evaluating the hazard to
humans exposed to formaldehyde.

183
EMBRYOTOXIC AND TERATOGENIC POTENTIAL

Formaldehyde has not been shown to be teratogenic in animals.
Pregnant dogs were fed diets containing formaldehyde (formalin in 40%
solution) at 125 or 375 ppm on days 4-56 of gestation. None of the 212
pups examined showed anomalies. Some of these pups were returned to
the breeding colony, and their offspring showed no abnormalities. 95

Rats were continuously exposed at 0.01 or 0.8 ppm for 20 d.
Halfway through the exposure period, the animals were mated. No gross
abnormalities were observed in the offspring, but there was an
increase in gestation time. The number of fetuses decreased with
increased formaldehyde concentration. However, the actual numbers of
offspring in the 0.8-ppm, 0.01-ppm, and control groups were 208, 235,
and 135, respectively. No explanation was given for the large
increase in offspring from the exposed rats, compared with
controls. 73 In another study, rats were exposed at 4.1 ppm for 4
h/d on days 1-19 of pregnancy. No effect on the course of pregnancy
or malformations in the fetuses were seen. 171 No alteration of
reproductive function was seen in male rats given formaldehyde at 0.1
ppm in their drinking water and 0.4 ppm in the air for 6 mo. 80

In a gavage study, pregnant outbred albino mice were fed
formaldehyde on days 6-15 of gestation. 123 The mice were sacrificed
on day 18; the general health and reproductive status of the dams were
evaluated, and the fetuses were examined for external, visceral, and
skeletal malformations. The formaldehyde, which contained 12-15%
methanol as a preservative, was lethal to 22 of 34 dams treated with
185 mg/kg per day and one of 35 dams treated with 148 mg/kg per day.
These doses did not produce statistically significant teratogenic
effects in the fetuses of the surviving dams (two-sided p_ < 0.05,
compared with controls) .

When dogs were fed hexaraethylenetetramine (which decomposes to
formaldehyde and ammonia in acid media) at 600 and 1,250 ppm on days
4-56 of gestation, no evidence of teratogenesis was observed. And
long-term feeding studies in rats given 1,600 ppm showed no effect on
reproductive capacity. 95

CARCINOGENIC POTENTIAL

A 90-d pilot study of formaldehyde was conducted by the CUT
(unpublished data) . Rats and mice were exposed to atmospheres
containing formaldehyde at 4, 12.7, or 40 ppm. The exposures were
conducted approximately 6 h/d, 5d/wk, for 13 wk (12 wk for the highest
concentration) . Other animals served as controls and were exposed
only to clean, filtered air. Exposure at 40 ppm resulted in
ulceration or necrosis of nasal turbinate mucosa in significant
numbers of animals of each species. Rats of both sexes had a high
incidence of tracheal mucosal ulceration and necrosis; only a few male
mice exhibited this lesion. Pulmonary congestion was prominent in
both male and female rats and male mice at the high dosage. Female
mice in the control and high-dosage groups had a similar incidence of

184

pulmonary congestion. Secondary lesions encountered in rats exposed at
40 ppm were apparently related to bacterial septicemia after severe
damage to respiratory tract mucosa. It was concluded that exposure at
40 ppm was lethal, but that exposure at 12.7 ppm was not lethal and
should be tolerable for an extended period. The pilot study was
followed by a study of Fischer 344 rats and B6C3F1 mice described in
the following abstract: 185

Groups of 120 male and 120 female rats were exposed by
inhalation to 0, 2, 6, or 15 ppm formaldehyde vapor 6
hr/day, 5 days/week, for 18 months of a 24-month study.
The present communication describes interim findings based
on data available after 18 months of exposure. Squamous
cell carcinomas occurred in the nasal cavities of 36 rats
exposed to 15 ppm formaldehyde. The tumors ranged from
small early carcinomas of the nasal turbinate to large
invasive osteolytic neoplasms which extended into the
subcutis of the premaxilla. Similar tumors were not
detected in rats exposed for 18 months to 2 or 6 ppm or in
mice exposed to 2, 6, or 15 ppm formaldehyde. Rhinitis,
epithelial dysplasia, and squamous metaplasia occurred in
rats from all exposure levels of formaldehyde; however, the
severity and extent of the lesions were dose related. In
contrast, papillary hyperplasia and squamous atypia
occurred only in animals exposed to 15 ppm formaldehyde.

This is the first experimental study to implicate formaldehyde as
a potential carcinogen, but the significance of these preliminary
findings can be evaluated only after completion of the study and
analysis of the pathologic findings. (The CUT reported at the
Formaldehyde Symposium on November 20-21, 1980, in Raleigh, N.C., that
nasal cancer had been observed in rats exposed at 6 ppm for 24 mo and
in mice exposed at 15 ppm for 24 mo.)

Mice (strain C3H) exposed to formaldehyde at 83 ppm, for 1 h/d, 3
d/wk, for 35 wk or at 41.5 ppm for 1 h/d, 3 d/wk, for 35 wk and at 125
ppm for an additional 29 wk had basal cell hyperplasia and squamous
cell metaplasia in the tracheobronchial epithelium, but no
tumors. 91 Hamsters exposed at 10 ppm for 5 h/d, 5 d/wk, for their
lifetime (average, 18 mo) had increased cell proliferation and
hyperplasia in the lungs (P. Nettesheim, unpublished data); weekly 5-h
exposures at 50 ppm for lifetime (18 mo) produced squamous metaplasia,
but no tumors. In neither of these studies was nasal tissue
specifically examined.

Injection-site sarcomas developed in two of 10 rats given weekly
injections of 0.4% aqueous formaldehyde for 15 mo. 20a Fibrosarcomas
were observed in the liver and omentum in two other rats. These
results are not useful, because of lack of controls and
inappropriateness of the route of administration.

A. R. Sellakumar et al. (personal communication) exposed
Sprague-Dawley rats to hydrogen chloride at a mean concentration of
10.6 ppm and formaldehyde at 14.7 ppm for 6 h/d, 5 d/wk, for their
lifetime. Before dilution to the stated concentrations in the

185

exposure chamber, the initial reaction mixture had average hydrogen
chloride and formaldehyde concentrations of about 6,500 and 1,000 ppm,
respectively; alkylating-agent activity of 1.8 ppm was also detected,
possibly as a result of the interaction of hydrogen chloride and
formaldehyde in the gas phase. Alkylating-agent activity in the
animal exposure chamber, as measured by chroma tog raphy, was 0.028
ppm. Of the 99 exposed animals, 25 developed squamous cell carcinomas
of the nasal epithelium. 169 No squamous cell tumors were observed
in controls. One of the alkylating agents identified in the chamber
was bis (chloromethyl) ether (BCME) , at a concentration of less than 1
ppb. BCME is a potent carcinogen; esthesioneuroepitheliomas of the
nose, squamous cell carcinomas of the lung and nasal turbinates, and
adenocarcinomas of the lung and nasal cavity have been produced in
rats after 10-100 exposures to BCME at 0.1 ppm for 6 h/d, 5 d/wk. 10fl

Published reports indicate that BCME should not be formed in
substantial amounts during chronic animal studies if concentrations of
both hydrogen chloride and formaldehyde are less than 100 ppm at
ambient temperature and humidity. 97 I89 However, Frankel et al. 67
studied the reactions of formaldehyde and hydrogen chloride in the
formation of BCME in glass vessels. They found that BCME is formed at
less than 0.5 ppb when formaldehyde and hydrogen chloride are each
present at 20 ppm, at less than 0.4 to 8.3 ppb (average, 2.7 ppb) when
they are present at 100 ppm, and at 5-59 ppb when they are present at
300 ppm. It was estimated that it would take longer than 18 h to
reach a steady state and concluded that further study was needed to
define the reaction kinetics. (See Chapter 5 for discussion of the
potential for the formation of BCME in the atmosphere.)

The carcinogenic potential of hexamethylenetetramine (HMT) , which
can decompose in an acid medium to release formaldehyde and ammonia,
has been examined. * 7 Mice and rats were given fresh solutions of
HMT in drinking water every 24 h at 0.5-5% for 30-60 wk and at 1-5%
for 2-104 wk, respectively. Mice were observed for up to 130 wk, and
rats for up to 3 yr. At 5% HMT, there was 50% mortality in the rats
after 2 wk. No significant effects on growth or survival were
observed in any of the other groups of rats or in the mice.
Histologic examination indicated that no effects were attributable to
HMT. No carcinogenic activity was observed.

EFFECTS IN HUMANS

The principal effect of low concentrations of formaldehyde
observed in humans is irritation of the eyes and mucous membranes.
Table 7-2 summarizes data on human responses to airborne formaldehyde
at various concentrations. It shows a wide range in formaldehyde
concentrations reported to cause specific health effects. The
severity of symptoms appears to be dose-related at extremes of
concentration. In general, at low concentrations, below 0.05 ppm, no
effects were reported. Objective changes in laboratory tests (i.e.,
optical chronaxy, EEC, etc.) without manifest symptoms were reported
at concentrations beginning at 0.05 ppm, but more often at 1.5 ppm and

186

TABLE 7-2
Reported Health Effects of Formaldehyde at Various Concentrations

Approximate
Formaldehyde
Concentration,
ppm

U-0.5
0.05-1.50
0.05-1.0

iealth Effects Reported
None reported
Neurophysiologic effects
Ddor threshold

Eye irritation

Upper airway irritation

Lower airway and pulmonary
effects

Pulmonary edema, inflam-
mation, pneumonia

Death

0.01-2.0 a

0.10-25

5-30

50-100

100+

References
65, 132,
65, 132, 198

15, 20, 65, 68,
112, 175, 207, 215,
217

61, 78, 133, 137,
163, 168, 175, 198,
207, 217

3, 9, 15, 20, 60,

102, 107, 134, 137,

173, 192, 198, 215,
217, 218

68, 71, 85, 86, 107,
151, 152, 167, 173,
198, 204, 215, 218

16, 152, 218
16, 152

a The low concentration (0.01 ppm) was observed in the presence of other pollutant
that may have been acting synergistically.

187

higher. The odor of formaldehyde is generally perceived by about 1
ppm, but some people can detect 0.05 ppm. variable nonspecific
complaints such as increased thirst, dizziness, headache, tiredness,
and difficulty in sleeping are difficult to evaluate; however, they
were generally reported when concentrations exceeded 1 ppm. Symptoms
of eye irritation were reported at concentrations as low as 0.05 ppm.
At concentrations at or above 1 ppm, nose, throat, and bronchial
irritation was noted. Such irritation was readily reported when the
concentration reached 5 ppm. When concentrations exceeded 50 ppm,
severe pulmonary reactions occurred, including pneumonia, bronchial
inflammation, and pulmonary edema, sometimes resulting in death.

Table 7-2 clearly shows the variability and overlap of responses
among subjects. Some persons develop tolerance to olfactory, ocular,
or upper respiratory tract irritation. Such factors as smoking habits,
socioeconomic status, preexisting disease, various host factors, and
interactions with other pollutants and aerosols are expected to modify
these responses.

EYE

Eye irritation is a common complaint of persons exposed to
formaldehyde vapor. 133 16B 175 207 217 Formaldehyde is detectable at
0.01 ppm, and at 0.05-0.5 ppm it produces a more definable sensation
of eye irritation. 61 163 198 Occupational exposures at 0.9-1.6 ppm
to formaldehyde released from paper pulp treated previously with
urea-formaldehyde or melaraine- formaldehyde resulted in complaints of
itching eyes, dry and sore throats, disturbed sleep, and unusual
thirst on awaking in the morning. 137 Eye, nose, and throat
irritation was reported by three of 16 subjects exposed for 5 h/d for
4 d at 0.3 mg/m 3 (0.2 ppm) and 15 of 16 subjects exposed at 1.0
mg/m 3 (0.7 ppm) in a chamber. 9 Sim and Pat tie 175 exposed 12 men
in an exposure chamber at 13.8 ppm for 30 min. There was considerable
nasal and eye irritation when the men first entered the chamber.
However, the eye irritation was reportedly not severe, and the
symptoms wore off after about 10 min in the chamber. Other studies
reported that eye irritation may occur at concentrations below 1
ppm. 133 lse 175 207 217 Marked irritation with watering of the eyes
occurs at a concentration of 20 ppm in air. 198 Eye damage from
formaldehyde vapor at low concentration is thought not to occur,
because of the protective closure of the eye that results from
discomfort. 78 Increased blink rates were noted at concentrations of
0.3-0.5 ppm in persons studied in so-called pure air irradiated in
smog chambers. 16B Blink rate, although used as an objective measure
of eye irritation, appears variable for any given subject. The
irritant effects of formaldehyde seem to be accentuated when it is
mixed with other gases. In 14 smog-chamber tests, there was an
average eye-irritation index of 4.9 1.0 units (on a scale of 0-24;
0-16, none to severe irritation, and over 16, lacrimation in more tha
50% of the subjects) . It was concluded that the human subjects teste>
could readily detect and react to formaldehyde at as low as 0.01 ppm.

188

A difference in the concentration-response curves for formaldehyde was
seen in the presence of photooxidation products of ethylene and
propylene. A linear relationship was noted between eye irritation and
formaldehyde concentration over a range of 0.3-1 ppm. It seemed that
formaldehyde and peroxyacetylnitrate accounted for 80% and 20%,
respectively, of the eye irritation associated with photochemical air
pollution. In the usual smog-chamber experiments, dilute mixtures of
nitric oxide, nitrogen dioxide, and hydrocarbons in air are
irradiated. The Committee is not certain about the extent to which
nitric acid, formic acid, and similar compounds shown to be present
since the earlier studies were done contributed to the eye irritation
observed in those experiments.

Accidental splash exposures of human eyes to aqueous solutions of
formaldehyde have resulted in a wide variety of injuries, depending on
concentration and treatment. These range from discomfort and minor
transient injury to delayed but permanent corneal opacity and loss of
vision. Immediate flushing with water spared the eyes of one worker
who received a splash injury from 40% formaldehyde solution. 100 A
similarly exposed coworker whose eyes were not flushed with water lost
vision in both eyes. Results of other accidental exposures to aqueous
formaldehyde in humans and experimental ocular studies in animals were
described by Grant. 78 Potts has shown that intravenous
administration of formaldehyde (at 0.9 g/kg) has a pronounced action
on retinal function, as indicated by changes in alpha and beta waves
of the electroretinogram that were correlated with ophthalmoscopic
retinal edema. l53 The changes would be missed if histology alone
were used to detect them. In a NIOSH study, a complete visual test
battery and ophthalmologic examination of workers exposed at 1.5 ppm
revealed no effects of formaldehyde on the eye. 210

In summary, human eyes are very sensitive to formaldehyde,
detecting atmospheric concentrations of 0.01 ppm in some cases (when
mixed with other pollutants) and producing a sensation of irritation
at 0.05-0.5 ppm. Lacrimation is produced at 20 ppm, but damage is
prevented by closure of the eyes in response to discomfort. Aqueous
solutions of formaldehyde accidentally splashed into the eyes must be
immediately flushed with water to prevent serious injury, such as lid
and conjunctival edema, corneal opacity, and loss of vision. Table
7-3 summarizes some of the studies concerning eye irritation.

OLFACTORY SYSTEM

The odor threshold of formaldehyde is usually around 1 ppm, but
may be as low as 0.05 ppm. 15 20 65 ^2 173 i?s 207 217 olfactory
fatigue with increased olfactory thresholds of rosemary, thymol,
camphor, and tar was reported among plywood and particleboard workers
and is presumed to be associated with formaldehyde exposure. 215

189

TABLE 7-3
Eye Irritation Effects of Formaldehyde

Formaldehyde

Concentration,

ppm

0.03-3.2

13.8
20

0.25
0.42

0.83-1.6

4-5

0.9-2.7
0.3-2.7
0.9-1.6

0.13-0.45

0.067-4.82
0.02-4.15
0.03-2.5

Exposure
Chamber single :

20-35 min; gradually
increasing concentra-
tion

30 min

Less than 1 min

Chamber repeated :
5 h/d for 4 d
5 h/d for 4 d

5 h/d for 4 d
Occupational :

Indoor residential:

Effects on Eyes Refer

Increase in blink rate; 21
irritation

Irritation (and nose 17
irritation)

Discomfort and lacrima- 1
tion

19% "slight discomfort"

31% "slight discomfort"
and conjunctival irrita-
tion

94% "slight discomfort"
and conjunctival irrita-
tion

Irritation, lacrimation,
and discomfort in 30 min

Tearing

Prickling and tearing 1

Intense irritation and 1
itching

Stinging and burning 2

Tearing

Irritation

Irritation

190
RESPIRATORY TRACT

The human nose adjusts the temperature and water-vapor content of
air and removes a large proportion of foreign gases and dusts, * 5 **
and the nasal mucociliary system clears foreign material deposited on
it. Nasal congestion from injury may lead to partial mouth-breathing;
when nasal functions are impaired or the nose is otherwise bypassed
for mouth-breathing, the burden of conditioning and cleaning the air
falls on the lung. If the nasal defense system is disturbed or if
mouth-breathing occurs, greater concentrations of formaldehyde will
reach the lungs, and other noxious materials that are ordinarily
cleared from the airways may be retained. In this regard, the
differences in breathing of rats and mice should be noted. Rats and
mice are obligatory nose breathers; therefore, nasal defense
mechanisms may be more important in these animals. Thus, with respect
to target organs for formaldehyde, it may be inappropriate to
extrapolate results of rat and mouse formaldehyde-inhalation
experiments directly to humans.

Upper Airway Irritation

Symptoms of upper airway irritation include the feeling of a dry
throat, tingling sensation of the nose, and sore throat, usually
associated with tearing and pain in the eyes. Irritation occurs over
a wide range of concentrations, usually beginning at approximately 0.1
ppm, but reported more frequently at 1-11 ppm 15 20 60 102 107 137 215 217
(see Table 7-2) . Tolerance to eye and upper airway irritation may
occur after 1-2 h of exposure. 15 102 173 However, even if tolerance
develops, the irritation symptoms can return after a 1- to 2-h
interruption of exposure. 3 1S 102 191 * 173 192 As in the case of eye
irritation, some persons seem to tolerate higher concentrations, 16-30
ppm perhaps subjects who developed tolerance.

When 16 healthy young subjects were exposed to formaldehyde at
0.25, 0.42, 0.83, or 1.6 ppm for 5 h/d for 4 d, nasal-mucus flow rate
was decreased at all concentrations except 0.83 ppm. 9 Subjective
responses to formaldehyde included slight conjunctival irritation and
dryness of the throat and the upper third of the nose.

Helwig reported that schoolchildren and teachers developed eye and
respiratory tract irritation, gastrointestinal disturbances, increased
thirst, and apathy after moving into a prefabricated school
building. 81 * The "new-building odor" was particularly strong after
weekends and holidays. Measurements of airborne formaldehyde made
with Drager tubes revealed concentrations of 5 ppm or more on one
occasion. Mild dysrhythmias were present in 20 children who underwent
EEC studies. No details were given regarding the medical complaints
or the number of children who developed adverse reactions while
attending classes. The author felt that plastic polymers used in
chipboard might also produce similar effects. Children who moved to
another building after graduation no longer had any symptoms.

Eye and upper respiratory tract irritation were noted in some
employees of funeral homes that used formaldehyde and paraformaldehyde

191

in the embalming process; airborne concentrations in the embalming
rooms were 0.25-1.39 ppm. ^2 & garment factory had airborne
concentrations of 0.9-2.7 ppm; 15 eye and upper respiratory tract
irritation were more common in areas where large quantities of
partially completed permanent-press materials accumulated.

The incidence of chronic rhinitis and pharyngitis was higher among
formaldehyde-exposed workers in a wood-processing facility than in a
control group. 198 218 A majority of workers complained of throat
irritation, diminished smell, and dryness of the nose and pharynx.
Examination of the nose and throat revealed hypertrophic or subtrophic
nasal mucosa and subtrophic or atrophic pharyngitis in almost half th
exposed workers. The incidence of pathology was highest in workers
with the most exposure to formaldehyde. Formaldehyde concentrations
reportedly ranged from 0.5 to 8.9 ppm, although occasional brief
excursions above this limit were also observed. This study of
wood-processing employees did not include measurements of other
airborne contamintants, such as wood dust. In another study, reduced
mucociliary function of the nasal mucosa and increased olfactory
threshold to rosemary, thymol, camphor, and tar were observed in
formaldehyde-exposed workers, compared with controls, regardless of
evidence of nasal pathology. 215

Nasal cancers in humans have been reported in some highly select
occupations, such as wood-working and work with nickel. 1 199
Because of the shape of and the high linear velocity of air in the
anterior part of the nose, a large portion of dust that enters the
nose is deposited in this portion. But the main nasal passage has a
large surface area and is narrow, and air in this portion has low
linear velocity; gases are therefore absorbed here. There maybe a
direct or indirect local effect of chemical agents or an inter ferenc.
with repair mechanisms at the sites of deposit or absorption. Furth.
research is necessary concerning the morphology of the nasal
turbinates and the histopathology of the nasal mucosa in rats, mice,
and humans before definitive comparisons can be made with respect to
exposure to specific chemicals, such as formaldehyde.

in summary, irritation of the nose and throat caused by
formaldehyde may occur at concentrations of Q '\**l' b ^
frpmientlv at 1-11 ppm. Examinations of the nose and throat
cnronfc changes thafare .ore severe In persons PJ
concentrations. Exposure to formaldehyde can cause alterations in

for animal carcinogenicity is discussed elsewhere in this report.

Lower Airway and pulmonary Effects

Lower airway irritation that is characterized clinically by cou
ches^ghtness! and whee^ , .reported * * pe^le exposed^

Perslnf apprenticed to ^aldehyde at high concentrations a

192

usually normal, except for occasional reports of accentuated
bronchovascular markings, but pulmonary- function test results may be
abnormal. 218 Acute respiratory distress was reported in a physician
after several hours of formaldehyde exposure. 152 Physical
examination of the physician's chest revealed diffuse rales and
occasional rhonchi. A chest x ray was interpreted as showing early
pulmonary edema. It is not known whether this case constitutes an
example of a hypersensitivity reaction to formaldehyde or acute
chemical pneumonitis. No specific information was given on the
exposure to formaldehyde.

Pulmonary-function studies of rubber workers exposed to a
hexamethylene-tetramine-resorcinol resin showed decreased pulmonary
function. 71 However, no association could be demonstrated between
concentrations of airborne resorcinol, formaldehyde, hydrogen cyanide,
or ammonia and change in pulmonary function. In a study of employees
who manufacture filters with fibers that are impregnated with
phenol-formaldehyde, a reduction in the ratio of FEVi to F7C,
expressed as percent, and maximal expiratory flow at 50% of vital
capacity were noted on Monday morning, compared with values of the
previous Friday, for employees who had worked more than 5 yr. 167
Detailed measurements of formaldehyde were not made, but two surveys
reported concentrations of 0.4-0.8 ppm and 9.14 ppm. The work
environment included other pulmonary irritants, such as phenol and
acrylic fiber breakdown products. Chronic cough and sputum production
occurred more often in those currently employed in production for over
5 yr than in those never involved in production, although little
change in pulmonary-function test results was noted during the course
of a workweek or workday.

The prevalence of respiratory illness and complaints among
employees in eight textile plants was more than 15% for four plants
and 5-15% for the other four. 173 These results were obtained from
medical records and were not confirmed through medical examination of
the employees. Airborne formaldehyde concentrations were 0-2.7 ppm,
with an average of 0.68 ppm. Workers reported that formaldehyde
concentrations varied considerably with changes in temperature and
humidity. It is not known whether the airborne formaldehyde
concentrations were representative of seasonal fluctuations.

Pulmonary edema, pneumonitis, and death could result from very
high formaldehyde concentrations, 50-100 ppm. 16 152 21B It is not
known what concentrations are lethal to humans, but concentrations
exceeding 100 ppm would probably be extremely hazardous to most and
might be fatal in sensitive persons.

Asthma

Allergic contact dermatitis caused by formaldehyde sensitivity is
well-recognized, but there have been relatively few documented cases
of occupational asthma attributable to formaldehyde and proved by
bronchial inhalation challenge tests. 85 86 110 1! 3 ^ lsl 16I 167
is* 20* In t he cases reported by Hendrick and Lane, nurses in a

193

renal hemodialysis unit developed asthma as a result of continued
exposure to formaldehyde that was used to sterilize the
artificial-kidney machines. 85 8S In all, eight of 28 persons
studied had experienced asthmatic attacks or bronchitis. In five of
the eight, attacks had been recurrent for at least 3 yr, and only on
had ever experienced such symptoms before joining the unit. Bronchi
provocation tests were positive in only two persons. In those two,
wheezing began approximately 2-3 h after exposure, and the results c
measured pulmonary function tests fell by as much as 50%. Reactions
persisted for from 10 h to 10 d, depending on the exposure;
concentrations in the air were not reported. The asthmatic reactior
could be inhibited by beclomethasone aerosol. '

Mechanism of Airway Responses to Formaldehyde

Formaldehyde has been shown to cause bronchial asthma in
humans . 8 s a e no 113 i a i s i i e * i e 7 1 9 n 2 o H Although asthmatic
attacks are in some cases due specifically to formaldehyde
sensitization or allergy, formaldehyde seems to act more commonly a
direct airway irritant in persons who have bronchial asthmatic atta
from other causes. Persons with bronchial asthma respond to numero
agents, such as exogenous irritants and allergens, respiratory
infections, cold air, smoke, dust, and stress. 22 7 "* The asthmatic
person seems to represent an extreme on the scale of respiratory
sensitivity to inhaled irritants. The data suggest a dose-response
relationship, with increasing numbers of asthmatics having attacks
air pollution worsens. Thus, the airways of asthmatics respond to
many nonspecific inhaled irritants, including formaldehyde.

The exact mechanism of the asthma syndrome related to formaldel
exposure is not known. It has been suggested that an immunologic
basis is sometimes operative. However, no studies have demonstrate
the presence of specific circulating immunoglobulins (IgE or IgG)
affected persons.

Non immunologic mechanisms may explain the effects of formaldeh
on the airways. Although formaldehyde at low concentrations may c
asthmatic symptoms in some sensitized subjects, in irritant
concentrations it produces bronchoconstriction in even normal
persons. The effect of lower concentrations on airways may be sin
to those of chemicals, such as toluene diisocyanate (TDI) , that at
concentrations not ordinarily considered irritating do produce an
adverse airway response unrelated to allergy, possibly on a
pharmacologic basis. 27 28 1SO l76 213 An abnormality of the
beta-adrenergic receptor system has been proposed as an explanati<
for asthma due to TDI. 27 2a Other possible pharmacologic mechanii
may be similar to those associated with cotton dust, cotton extra*
have been reported to cause histamine release from basophils. 19

Inhalation of formaldehyde vapors may itself act directly on
smooth muscle or nerve endings, causing airway hyperreactivity, a
important component of bronchial asthma. ^ ll1 ll 9 182 Methachol

194

and histamine challenge tests have demonstrated this hyperreactivity
with other environmental pollutants. 21 22 26 28 7>t

Recently, alterations in the bronchial mucosal epithelial barrier
have been proposed as a theory to explain the effects of environmental
agents on airways. 18 88 Normally, the bronchial mucosa provides a
barrier, preventing entry of high-molecular-weight protein into the
submucosal layer . Environmental agents can increase both the
permeability of the bronchial epithelium and the response to histamine
at subthreshold concentrations. The disruption of the bronchial
epithelial barrier, perhaps the tight junction between cells, permits
the environmental and pharmacologic agents better access to the
underlying tissue and the capability of reaching afferent nerve fibers
that are directly beneath the tight junctions of the epithelial
cells. This greater accessibility to the nerve fibers leads to the
apparent fncreased reactivity of airways. In addition, formaldehyde
may be able to act directly on bronchial smooth muscle beneath the
epithelial barrier. 101 Nonspecific mast-cell degranulation from
formaldehyde, resulting in release of vasoactive substances and
causing smooth-muscle contraction, is another possible nonimmunologic
mechanism.

Summary

A number of lower airway and pulmonary effects may occur from
formaldehyde exposure. In most normal persons exposed to
formaldehyde, concentrations greater than 5 ppm will cause cough and
possibly a feeling of chest tightness. It is possible that normal
persons will experience these symptoms at 2-3 ppm, but data are not
available on this. In some susceptible persons, concentrations below
5 ppm can cause these symptoms, including wheezing. In persons with
Bronchial asthma, the irritation caused by formaldehyde may
precipitate an acute asthmatic attack, possibly at concentrations
Delow 5 ppm. Rarely does a person with asthma become sensitized
(allergic) specifically to formaldehyde and thereby respond to
concentrations lower than 0.25 ppm. This reaction is not due to
formaldehyde's irritant properties, but is related to some poorly
mderstood immunologic (or possibly nonimmunologic) mechanism. In
concentrations greater than 50 ppm, severe lower respiratory tract
iffects can occur, with involvement not only of the airways, but also
>f alveolar tissue. Acute injury of this type includes pneumonia and
Loncardiac pulmonary edema.

'.KIN

Skin contact with formaldehyde has been reported to cause a
ariety of cutaneous problems in humans, including irritation,
llergic contact dermatitis, and urticaria. 1 ** 162 18 Allergic
ontact dermatitis from formaldehyde is relatively common, and
ormaldehyde is one of the more frequent causes of this condition both

195

in the United States* 6 and in other areas.es The North American
Contact Dermatitis Group reported that formaldehyde is the tenth
leading cause of skin reactions among dermatitis patients patch-tested
for allergic contact dermatitis. Approximately 4% of 1,200 patients
had positive skin reactions when tested with 2% formalin (0.8%
formaldehyde) under an occlusive patch."* Minor epidemics of
allergic contact dermatitis have been described in diverse situations,
for example, among nurses who handled thermometers that had been
immersed in a 10% solution of formaldehyde 161 and among those who
were exposed to formaldehyde in hemodialysis units. 180

In many cases, either the initiation or the elicitation of the
allergy has been caused by contact with formaldehyde or formalin, but
it may also result from formaldehyde-releasing agents used in
cosmetics, medications, and germicides, from incompletely cured
resins, and from the decomposition of formaldehyde-containing resins
used in textiles. 115 People with cutaneous allergy to formaldehyde
have particular problems because there are so many sources of
formaldehyde exposure in ordinary daily life. For example, the FDA
lists 846 cosmetic formulations containing formaldehyde. 201 The
skin reaction rate from cosmetic formulations containing formaldehyde
has not been excessive, because it is used mainly as a preservative- in
shampoos, whose contact time with skin is short. Formaldehyde-
releasing cosmetic preservatives, such as Quaternium-15, have shown a
greater reaction frequency than formaldehyde itself (unpublished data
from Cosmetics Technology Division, Bureau of Foods, FDA).

Humans can come into contact with low concentrations of
formaldehyde from many sources, and repeated contact with them may be
sufficient to provoke responses in people with allergic contact
sensitization. It is important to mention that previously "normal"
people can become sensitized. These sources include components of
plastics, glues, antifungal disinfectants, preservatives, paper,
fabrics, leather, coal and wood smoke, fixatives for histology, and
photographic materials. 70 Available data do not permit the
determination of a degree of exposure to formaldehyde-containing
products that would be safe once sensitization has occurred.

Occupational dermatitis from urea- formaldehyde dusts and powders
(containing free formaldehyde) in the workplace was reported by
Harris. 81 Exposed skin e.g., on the face, lips, and neck and in
interdigital areas was affected, as well as such permeable skin sites
as the scrotum and eyelids and intertriginous areas, such as the
armpit and flexure areas of the arms.

The response of formaldehyde-sensitive persons is related to the
extent of exposure (see Table 7-4). 126 However, most sensitized
persons can tolerate topical axillary products containing formaldehyde
at up to about 30 ppm. 96 With increasing concentration, one sees a
higher frequency of responders, l 27 probably because skin penetration
by formaldehyde varies from one person to another and even from one
site to another on the same person. Thus, different amounts of
formaldehyde may reach different target sites. The dose needed to
elicit a response depends on these factors and others, such as
occlusion, temperature, contact time, and vehicle.

196

TABLE 7-4

Elicitation (Occluded) of Skin Reactions in
Five Formaldehyde-Sensitized Subjects 8

Formaldehyde

Challenge No.

Concentration, Responding

% (n => 5)

1 4

0.5 2

0.2 1

0.1 1

0.01 1

I tyc.

a Data from Marzulli and Maibach.

197

Allergic contact dermatitis is a manifestation of cell-mediated
immunity. The standard diagnostic test for this condition is the
epidermal patch test, in the case of formaldehyde, interpretation may
be complicated by the irritant potential of the substance. Patch
testing is now generally conducted with a 2% concentration of
formalin. Before the early*1970s, a 5% solution in water was commonly
used; many of the reported results of earlier patch testing may have
been spurious. ** Patch testing for skin sensitization to
formaldehyde resin is performed with a 5-10% concentration of the
resin in petrolatum. 2

So-called predictive tests for skin sensitization are used first
on animals, then on man to identify the allergenic potential of new
substances or formulations entering the marketplace. Guinea pigs are
the favored animal species. The Draize intraderraal technique* 9 and
one of the published adjuvant techniques 125 are animal methods often
used before human investigation in evaluating skin hypersensitivity.
The Draize technique is likely to underestimate the human response,
whereas adjuvant (Freund's complete adjuvant) techniques are likely t
overestimate it. In human predictive testing, two techniques are
useful: the "modified Draize" 127 and the "maximization" 1011
methods. Results obtained for formaldehyde with some of these
techniques are compared in Table 7-5.

Although formaldehyde has been reported to cause contact
urticaria, it is not yet clear whether this is immunologically
mediated. ^^ Formaldehyde is a potent sensitizer and irritant,
repeated exposure to it may also result in dermatitis.

In summary, formaldehyde is a skin irritant and skin sensitizer.
Formaldehyde plastics sensitize skin by contact with formaldehyde
resin or by releasing formaldehyde from incompletely cured plastic
dusts or particles. Aqueous formaldehyde solutions (e.g., cosmetic
formulations) elicit a skin response (under occlusive cover) in some
sensitized people at concentrations as low as 0.01%, but underarm
products containing up to 0.003% formaldehyde are tolerated by most
sensitized persons. Formaldehyde-releasing preservatives, such as
Quaternium-15 , may sensitize to formaldehyde or to the parent
material. Occupational exposure to free formaldehyde in
urea-formaldehyde dusts and powders may also result in dermatitis.

CENTRAL NERVOUS SYSTEM

Central nervous system responses to formaldehyde have been teste
in a variety of ways, including by determination of optical
chronaxy,i32 electroencephalographically, 6S and by the sensitivity
of the dark-adapted eyes to light. 132 Responses are reported in
some persons at 0.05 ppm and are maximal at about 1.5 ppm.
Formaldehyde at less than 0.05 ppm probably has little or no objectj
adverse effect. 198 Fel'dman and Bonashevskaya reported that
formaldehyde at 0.032 ppm produced no electroencephalographic change
and did not reach the odor threshold in five extremely sensitive

198

TABLE 7-5

Predictive Skin-Sensitization Test Results with
Aqueous Formaldehyde

Positive-Response
Species Method Frequency, %

119
Guinea pig Draize intradermal 5

Adjuvant (maximization) 80 119

Human Maximization 72 119

Modified Draize 4.5-7.8 127

199

subjects. 65 Melekhina demonstrated sensitivity of the dark-adapted
eye to light at about 0.08 ppm. 132

ALIMENTARY TRACT

Ingestion of formaldehyde has been reported to cause headache,
upper gastrointestinal pain, 23 51 57 105 122 a allergic
reactions, 19 * corrosive effects on gastrointestinal and respiratory
tracts, 57 is lllt and systemic damage. 57 105 ll * Accidental or
suicidal poisoning with formaldehyde usually involves the ingestion
aqueous solutions; death occurs after the swallowing of as little as
30 ml of formalin. 16 105 Gastrointestinal tract damage is most
marked in the stomach and lower esophagus, with the tongue, oral
cavity, and pharynx generally not severely affected. 198 The small
intestine may occasionally be involved; perforated appendix is a ra
complication. When the chemical infiltrates around the epiglottis,
injury to the larynx and trachea may occur. 16 105 19B After
ingestion, there may be loss of consciousness, vascular collapse,
pneumonia, hemorrhagic nephritis, and spontaneous abortion. 16 10S
One autopsy report of a fatal ingestion described hardening of orga
adjacent to the stomach (lung, liver, spleen, and pancreas), hypere
and edema of the lungs, bilateral diffuse bronchopneumonia, fatty
degeneration of the liver with subcapsular hemorrhage, renal tubula
necrosis, and involvement of the brain. 16 10S 157

Other avenues of acute poisoning include intravesical instillal
of formalin for control of intractable bladder hemorrhage 36 and
accidental irrigation of the colon with aqueous formaldehyde. 91 *
Paresthesia, soft-tissue necrosis, and sequestration of bone have
occurred when formaldehyde preparations have been used for
devitalizing dental pulps. 79 8S 13S An outbreak of hemolytic anem
among patients at a hemodialysis unit was traced to formaldehyde
leaking from water filters impregnated with a melamine-formaldehyd
resin. 1!t s

EFFECTS ON REPRODUCTIVE SYSTEM

Menstrual abnormalities and complications of pregnancy were
reported to occur more frequently in Russian women employed in th
textile industry and in contact with urea-formaldehyde resins. 171 *
The unique role, if any, of formaldehyde in this study is not cle<
because of the lack of information, e.g., on other potentially toa
compounds in the workplace that might adversely affect the
reproductive system, on the composition and comparability of the
populations that were the source of the reported data, and on var
demographic, socioeconomic, and physiologic factors. Never theles,
is pertinent to summarize what was reported. Formaldehyde
concentrations were 1.5-4.5 yg/m 3 for high-exposure trimmers,
0.3-0.7 yg/m 3 for sorters, and 0.05-0.1 yg/m for others.
About 70% of the women were under 40 yr old. Menstrual disorders

200

encountered more often in women with greater exposures (trimmers) and
in direct relationship to duration of employment. Oligodysmenorrhea
was the major menstrual disorder: 24.3 2.2% of the trimmers, 20.2
2.2% of the sorters, and 9.2 1.1% of the controls.
Complications of pregnancy were more prevalent in the more exposed
group. Anemia, as a complication, was noted twice as often in the
exposed group. Other complications such as intrauterine asphyxia,
premature rupture of the membranes, late toxemia, threatened abortion,
and premature deliveries were analyzed and said to be more frequent
in the exposed groups, but no substantial analysis was reported.
There was also a greater percentage of newborns with low birthweight
in the exposed groups. Of the infants born to women who had contact
with formaldehyde, 26.9 4.9% weighed 2,500-2,990 g at birth,
compared with 11.3 1.3% of the infants born to women in the
control grup ( < 0.05) .

BLOOD

Hemolysis has been observed among patients undergoing chronic
hemodialysis . It resulted in contamination of several lots of
dialysis water with an excess formaldehyde concentration of 10
mmol/L. 1 * 5 Water filters treated with melamine-formaldehyde resin
were the source of the contaminated formaldehyde. A concentration as
low as 0.1 mM caused decreased ATP content when incubated with blood
cells. There is also evidence that formaldehyde sterilization of
dialyzers may cause antibody-mediated hemolysis that contributes to
renally induced anemia. 62

CONSUMER COMPLAINTS IN RESIDENTIAL ENVIRONMENTS

Over the last several years, increasing numbers of complaints have
caused concern about the health hazards of residing in homes where
formaldehyde is released into the living space. The Consumer Product
Safety Commission (CPSC) received more than 1,000 complaints from
users of mobile homes and conventional homes insulated with UF foam by
March 1980. * 3 l * * 19S 197 The Department of Housing and urban
Development reported an increase in complaints about formaldehyde
during this same period. On August 1, 1979, the CPSC issued a
consumer advisory on UF insulation, citing possible health problems
associated with this type of insulation. 131 * 19S

A number of studies have been undertaken to determine the
magnitude and extent of formaldehyde exposure of persons in the
residential environment. 3 2 * 30 ? 7 87 i** ^z iss 211 In 1975,
Anderson et^al. 10 reported formaldehyde concentrations ranging from
0.08 to 2.24 mg/m 3 , with an average of 0.62 mg/m 3 , in 25 rooms in
23 conventional Danish homes with chipboard in their interior
construction, in 1977, Breysse reported four cases (investigated
in 1961) in which people in conventional buildings had complained of
eye and upper respiratory irritation in association with exposure to

201

formaldehyde from particleboard and chipboard. In a compilation of
periodic investigations (1968-1977) of complaints, he noted 74 raobilt
homes, six of which were unoccupied, in which 92 persons experienced
adverse reactions "allegedly" resulting from exposure to formaldehyde
The range of concentrations reported was 0-2.5 ppm; fewer than 10%
were above 1.0 ppm. The prevalence of symptoms in the 92 people was
reported as follows: eye irritation, 80 persons; nose irritation, i:
respiratory tract irritation, 58; headache, 51; nausea, 12; and
drowsiness, 26. Severity of symptoms was not correlated with
formaldehyde concentration. However, it should be pointed out that
people questioned noted relief of symptoms when they left their home,
for the weekend and return of symptoms when they went home.

In November 1977, the Connecticut Department of Health and
Consumer Protection began receiving complaints from state residents
who had UF foam insulation installed in their homes. 77 By September
1978, 84 complaints had been received. The Department tested the 84
homes and found formaldehyde in the air in 75. The sensitivity of t
testing system was reported to be less than 0.05 ppm. Health symptom
were reported by 224 residents of 74 homes, in which detectable
concentrations of formaldehyde ranged between 0.5 and 10 ppm, with a
mean of 1.8 ppm. The symptoms of the residents included eye, nose,
and throat irritation; GI tract symptoms; headache; skin problems; s
some miscellaneous complaints, such as fatigue, aches, and swollen
glands. In 37%, however, symptoms occurred when formaldehyde was nc
detectable by the methods used. When formaldehyde was detectable
(0.5-10 ppm), 49% of the occupants had eye irritation, 37% nose and
throat irritation, 46% headache, and 22% GI tract symptoms; in homes
with no detectable formaldehyde, 26% had eye symptoms, 41% nose and
throat irritation, 26% headache, and 42% GI tract symptoms.

Since January 1978, the Wisconsin Division of Health has collet
air samples and environmental data on 100 mobile homes, conventiona
homes, and offices that have particleboard in their construction am
foam insulation. 46 Air samples were collected in midget impingers
and analyzed with the chromotropic acid procedure. Health informat
was obtained from the occupants of these structures. Formaldehyde
ranged from undetectable to 4.18 ppm. The median concentration was
0.35 ppm (0.47 ppm for mobile homes and 0.10 ppm for conventional
homes) . The symptoms observed included eye and upper respiratory
tract irritation, headache, fatigue, nausea, vomiting, diarrhea, an
respiratory problems. As formaldehyde concentrations increased, th
percentage of persons experiencing eye irritation increased frm 60%
92%. Among infants and young children, vomiting, diarrhea, and
respiratory problems were identified as particularly important
conditions. The relationship between smoking and formaldehyde
concentration in the dwelling was examined; smoking did not
significantly increase formaldehyde concentration in the home at tl
time of concentration measurement.

Consumer reports have also been summarized by the CPSC. 196
In-depth investigations of 15 persons were conducted by the CPSC f:
staff and by private contractors. Most of the reported symptoms w
related to eye and throat irritation. Five persons were admitted 1

202

the hospital for medical problems attributed to formaldehyde. The
CPSC also collected more than 100 reports from newspaper clippings,
consumer complaints, and state reports that were not investigated in
detail.

NONSPECIFIC SUBJECTIVE SYMPTOMS IN EXPOSED POPULATIONS AND EFFECTS ON
INFANTS AND CHILDREN

Various subjective and nonspecific complaints have consistently
been reported, including disturbed sleep, thirst, headache, and
nausea. 20 2<l sa fll 8lf 92 137 17S 19 19e 212 21S

Recently, there has been concern about the effects of formaldehyde
on infants and children. 21 * 1 The Wisconsin Division of Health
conducted a survey between January 1, 1978, and November 1, 1979, that
consisted of analysis of information collected with a questionnaire
completed by 249 persons, representing 96 homes and 260 occupants.
Two frequent findings were "nosebleed" and "rash" in infants and young
children. Nine of 23 infants (less than a year old) required
hospitalization; four were hospitalized for vomiting, diarrhea, or
both and five for respiratory problems. Three of the latter five also
had vomiting, diarrhea, or both. The mean formaldehyde concentration
in the homes of the hospitalized infants was 0.68 0.66 ppm. In
each case, symptoms reportedly disappeared when the infant was removed
from the home and returned when the infant went home.

OCCUPATIONAL STANDARDS FOR FORMALDEHYDE

Occupational exposure limits issued by various countries are
listed in Table 7-6. The present OSHA standard for formaldehyde is 3
ppm, as a time-weighted average concentration over an 8-h workshift.
In 1974, the ACGIH recommended a ceiling limit of 2 ppm, mainly
because irritation might occur above this concentration. NIOSH has
recommended a workplace ceiling limit of 1 ppm. 19e

RESIDENTIAL STANDARDS FOR FORMALDEHYDE

Occupational standards for formaldehyde have been determined in
the United States and other countries, but the recommendations are for
maximal time-weighted 8-h average concentrations for the workplace and
for ceiling or peak concentrations. In the United States, there is no
standard for formaldehyde for 24-h continuous nonoccupational
exposure, as in the home. The American Industrial Hygiene Association
has recommended an outdoor ambient-air standard of 0.10 ppm. 7 A
panel of the National Research Council has stated that airborne
formaldehyde in spacecraft for manned space flights should not exceed
0.10 ppm for an exposure of 90 d to 6 mo. " The American Society
of Heating, Refrigerating and Air-Conditioning Engineers has
recommended 0.20 ppm as a 24-h residential exposure limit.' West

203

TABLE 7-6
Occupational Standards for Formaldehyde in Effect, 1976 a

Country
United States:

Standard
mg/m j ppm

Type

Federal Standard

3

TWA

5

Ceiling

10

30-min ceiling

AOGIH TLV

2.5

2

Ceiling

ANSI Z-37

3

TWA

5

Ceiling

10

30-min ceiling

Florida

5

Ceiling

Hawaii

10

Ceiling

Massachusetts

3

Ceiling

Mississippi

5

Ceiling

Pennsylvania

5

TWA

5

5-min ceiling

South Carolina

___

5

Celling

Bulgaria

5

Ceiling

Czechoslovakia

2

Ceiling

5

Peak

Federal Republic of Germany

b

5

Ceiling

Finland

6

5

Ceiling

German Democratic Republic

5

Ceiling

Great Britain

12

10

Ceiling

Hungary

1

Ceiling

Italy

5

Ceiling

Japan

6

5

Ceiling

Poland

5

Ceiling

Rumania

3

Ceiling

UAR

20

Ceiling

USSR

0.5

0.4

Ceiling

Yugoslavia

6

5

Ceiling

Modified from NIOSH. 198

204

Germany, Denmark, and The Netherlands have residential standards of
0.10, 0.12, and 0.10 ppm, respectively (C.D. Hollowell, personal
communication; Hollowell et al.. 89 ). Sweden has recommended that a
standard be set in the range of 0.10-0.70 ppm. 192

SIGNIFICANCE OF ADVERSE HEALTH EFFECTS IN REGARD TO POPULATION AT RISK

The total number of people who are exposed to formaldehyde and who
manifest adverse health effects is difficult to determine. There is
evidence that such responses may occur in a substantial proportion of
the exposed population in the United States. The variability in
response among exposed persons makes it particularly difficult to
assess the problem.

People are exposed to formaldehyde from occupational sources,
consumer products, outdoor ambient air, and indoor air.

In the occupational setting, about 1.4 million persons are
directly or indirectly exposed to formaldehyde. It is not possible to
determine exactly the exposure in each industry. However, owing to
the irritant nature of formaldehyde, most workplaces probably have
concentrations of less than 3 ppm more often around 1 ppm or less for
an 8-h workday.

Some 11 million persons live in homes that contain either UF foam
insulation or particleboard made with UF resins. When measurements
have been performed, a wide range of formaldehyde concentrations from
0.01 ppm to 10.6 ppm, have been reported. Most homes have shown less
than 0.5 ppm with a range of 0.1-0.2 ppm being more prevalent.
Because people spend up to 70% of their time indoors, the exposure to
formaldehyde released from UF foam or particleboard could be
substantial.

Formaldehyde concentrations measured in ambient air are lower than
in the occupational or indoor residential situation. Outdoor
concentrations vary, but are rarely more than 0.1 ppm and usually less
than 0.05 ppm. However, the probability of high outdoor exposure to
formaldehyde for the 220 million people in the United States does not
appear to be substantial, except for unusual circumstances of traffic,
fuel use, or automobile density. Consumer exposures are mainly by
direct contact, and contact dermatitis is an important consideration,
as has been discussed.

Little is known about the magnitude of the population that is more
susceptible to the effects of inhaling formaldehyde vapor. Asthmatics
may constitute a segment of the general population that is more
susceptible; inhalation even at low concentrations may precipitate
acute symptoms. Airway hyperactivity may explain the susceptibility of
asthmatics to formaldehyde at low concentrations. Using data gathered
from over 1,500 methacholine challenge tests, one can estimate the
prevalence of airway hyperreactivity in the population at large. 19
About 9 million people in the United States have bronchial asthma.
Essentially all will react positively to methacholine challenge tests
and thus be considered to have hyper reactive airways. 190 The degree
of airway reactivity is variable and depends on a number of

205

factors. 22 It has been estimated that 30% of atopic nonasthmatic
people perhaps 10 million have positive methacholine tests. 190
Townley e_t al^. reported that 5% of nona topic persons another 8.5
million have positive methacholine tests. 190 Therefore, on the
basis of calculations reported for positive methacholine challenge
tests, it can be estimated that about 25 million persons in the United
States, or 10-12% of the population, may be considered to have some
degree of airway hyperreactivity. This population could potentially be
more susceptible to formaldehyde.

Information on other assumed susceptible populations is limited.
The U.S. Department of Health, Education, and Welfare, in a 1977
report on prevention, control, and elimination of respiratory disease,
estimated that 10 million persons in the United States had chronic
obstructive lung disease (excluding asthma). 200 A small percentage
of them will have positive methacholine challenge tests. Britt et_
al_. 25 suggested that the presence of methacholine sensitivity and
evidence of airway hyperreactivity are risk factors for the
development of chronic obstructive pulmonary disease (COPD) . Perhaps
patients with COPD who manifest airway hyperreactivity constitute a
susceptible population, inasmuch as they react more acutely to
airborne irritants, including formaldehyde.

On the basis of sensitivity to methacholine, some atopic persons,
some nonatopic subjects, and some COPD patients may constitute a
potential formaldehyde-susceptible population. This population could
also have greater eye and upper respiratory tract sensitivity.
However, many apparently normal people react to the irritant
properties of formaldehyde, and this makes it more difficult to
determine the susceptible population.

In another attempt to estimate the susceptible population
(particularly in relation to eye, nose, and throat sensitivity) ,
information on a small number of healthy young adults exposed to
formaldehyde at various concentrations for short periods was
considered. 139 At 1.5-3.0 ppm, more than 30% of the subjects tested
reported mild to moderate eye, nose, and throat (ENT) irritation
symptoms, and 10-20% had strong reactions. When test subjects were
exposed at 0.5-1.5 ppm, slight or mild ENT irritation was noted in
more than 30%, but 10-20% still had more marked reactions.
Approximately 20% of the subjects had slight ENT irritation in
response to formaldehyde at 0.25-0.5 ppm. Finally, at the lowest
concentration tested, less than 0.25 ppm, some exposed subjects ("less
than 20 percent") still reported minimal to slight ENT discomfort.
These data might be interpreted as suggesting that there are subjects,
perhaps 10-20% of those tested, who are more responsive and may react
acutely to formaldehyde at very low concentrations.

Data on the proportion of the population susceptible to the
irritant effects of formaldehyde seem to be consistent. The estimated
prevalence of airway hyperreactivity (based on methacholine challenge
testing) in the general population is 10-12% and about 10-20% of the
subjects in the study just described showed excessive ENT
sensitivity. We may get further information from mobile-home surveys
from which environmental and clinical data are available. No

206

measurements of other airborne contaminants were made, so the
importance of other substances in the household environment is not
known. Irritation symptoms were reported by 30-50% of subjects when
formaldehyde concentrations were greater than 0.5 ppm. When the
concentration was less than 0.5 ppm, irritation symptoms were reported
in fewer than 30% of subjects. Finally, in a more controlled study in
which irritation symptoms were investigated, mild irritation responses
(doubling of blinking rate) occurred in 11% subjects tested at 0.5 ppm,

In summary, fewer than 20% but perhaps more than 10% of the
general population may be susceptible to formaldehyde and may react
acutely at very low concentrations, particularly if they are above 1.5
ppm. People report mild ENT discomfort and other symptoms at less
than 0.5 ppm, with some noting symptoms at as low as 0.25 ppm.
Low-concentration formaldehyde exposures may produce ENT symptoms and
possibly lower-airway complaints. In some susceptible persons, an
"allergic" reaction to formaldehyde may occur at very low
concentrations, causing bronchoconstriction and asthmatic symptoms.
This particular type of reaction to formaldehyde appears to be
uncommon; its exact prevalence cannot now be estimated.

REFERENCES

Acheson, E. D., R. H. Cowdell, E. Hadfield, and R. G. Macbeth.

Nasal cancer in woodworkers in the furniture industry. Br . Med.

J. 2:587-596, 1968.

Adams, R. Occupational Contact Dermatitis. Philadelphia: J.B.

Lippincott Co., 1969. 262 pp.

Ad Hoc Task Force Epidemiology Study on Formaldehyde.

Epidemiological Studies in the Context of Assessment of the

Health Impact of Indoor Air Pollution. Summary and

Recommendations. Bethesda, Md.: Consumer Product Safety

Commission, May 10, 1979.

Altshuller, A. P., T. A. Bellar, and S. P. McPherson.

Hydrocarbons and Aldehydes in the Los Angeles Atmosphere.

Presented at Air Pollution Control Association Annual Meeting ,

May 2, 1962, Chicago, Illinois. Cincinnati: U.S. Department of

Health, Education, and Welfare, Division of Air Pollution,

Public Health Service, 1962.

Altshuller, A. P., L. G. Leng, and A. F. Wartburg. Source and

atmospheric analyses for formaldehyde by chromotropic acid

procedure. Int. J. Air Water Pollut. 63:381-385, 1962.

Amdur, M. 0. The response of guinea pigs to inhalation of

formaldehyde and formic acid alone and with a sodium chloride

aerosol. Int. J. Air Pollut. 3:201-220, 1960.

American Industrial Hygiene Association. Community air quality

guides. Am. Ind. Hyg. Assoc. J. 29:505-512, 1968.

American Society for Heating, Refrigerating and Air-Conditioning

Engineers. Standards for Natural and Mechanical Ventilation.

ASHRAE Standard 62-73. New York: ASHRAE, Inc., 1979.

207

9. Andersen, I. Formaldehyde in the indoor environment health
implications and the setting of standards, pp. 65-77, and
discussion, pp. 77-87. In P. 0. Fanger and O. Valbj^rn, Eds.
Indoor Climate. Effects on Human Comfort, performance, and
Health in Residential, Commercial, and Light-Industry Buildings.
Proceedings of the First International indoor climate Symposium,
Copenhagen, August 30-September 1, 1978. Copenhagen: Danish
Building Research institute, 1979.

10. Andersen, I., G. R. Lundqvist, and L. Molhave. Indoor air
pollution due to chipboard used as a construction material.

Atmos. Environ. 9:1121-1127, 1975.

11. Auerbach, C., M. Moutschen-Dahmen, and J. Moutschen. Genetic
and cytogenetical effects of formaldehyde and related
compounds. Mutat. Res. 39:317-362, 1977.

12. Babior, B. M. Folate and aplasia of bone marrow. N. Eng. J.
Med. 298:506-507, 1978.

13. Barnes, E. C., and H. W. Speicher. The determination of
formaldehyde in air. J. Ind. Hyg. Toxicol. 24:10-17, 1942.

14. Bilimoria, M. H. The detection of mutagenic activity of
chemicals and tobacco smoke in a bacterial system. Mutat. Res.
31:328, 1975.

15. Blejer, H. P., and B. H. Miller. Occupational Health Report of
Formaldehyde Concentrations and Effects on Workers at the Bayly
Manufacturing Company, Visalia. Study Report No. S-1806. Los
Angeles: State of California Health and Welfare Agency,
Department of Public Health, Bureau of Occupational Health,
1966. 6 pp.

16. Bohmer, K. Formalin poisoning. Dtsch. Z. Gesamte Gerichtl. med.
23:7-18, 1934. (in German)

17. Botez, M. I., J.-M. Peyronnard, J. Bachevalier, and L. Charron.
Polyneuropathy and folate deficiency. Arch. Neurol. 35:581-584,
1978.

18. Boucher, R. C. , P. D. Pare, and J. C. Hogg. Relationship
between airway hyperreactivity and hyperpermeability in
Ascaris-sensitive monkeys. J. Allergy Clin. immunol.
64:197-201, 1979.

19. Bouhuys, A., and K. P. van de Woestijne. Respiratory mechanics
and dust exposure to byssinosis. J. Clin. Inv. 49:106-118, 1970

20. Bourne, H. G., Jr., and S. Seferian. Formaldehyde in
wrinkle-proof apparel produces. . .tears for milady. Ind. Med.
Surg. 28:232-233, 1959.

21. Boushey, H. A., D. W. Empey, and L. A. Laitinen. Meat wrapper's
asthma. Effects of fumes of polyvinyl chloride on airways
function. Physiologist 18:148, 1975.

22. Boushey, H. A., M. J. Holtzman, J. R. Sheller, and J. A. Nadel.
Bronchial hyperreactivity. Am. Rev. Respir. Dis. 121:389-413,
1980.

23. Bower, A. J. Case of poisoning by formaldehyd. J. Am. Med.
Assoc. 52: 1106, 1909.

208

24. Breysse, P. A. Formaldehyde exposure following urea-
formaldehyde insulation. Environ. Health Safety News 26, 1978.
13 pp.

25. Britt, E. J., B. Cohen, H. Menkes, E. Bleecker, S. Permutt, R.
Rosenthal, and P. Norman. Airways reactivity and functional
deterioration in relatives of COPD patients. Chest

77 (Suppl.): 260-261, 1980.

26. Butcher, B. T-, R. M. Karr, C. E. O'Neil, M. R. Wilson, V.
Dharmarajan, J. E. Salvaggio, and H. Weill. Inhalation
challenge and pharraacologic studies of toluene diisocyanate
(TDI) -sensitive workers. J. Allergy Clin. Immunol. 64: 146-152 /
1979.

27. Butcher, B. T. , J. E. Salvaggio. C. E. O'Neil, H. Weill, and O.
Garg. Toluene diisocyanate pulmonary disease:

Immunopharmacologic and mecholyl challenge studies. J. Allergy
Clin. Immunol. 59:223-227.

28. Butcher, B.T., J. E. Salvaggio, H. Weill, and M. M. Ziskind.
Toluene diisocyanate (TDI) pulmonary disease: Immunologic and
inhalation challenge studies. J. Allergy Clin. Immunol.
58:89-100, 1976.

29. Cantor, T. R. Experience with the determination of atmospheric
aldehydes, pp. 514-515. In Automation in Analytical Chemistry.
Technicon Symposia 1966. Vol. I. New York: Mediad, Inc., 1967.

30. Carbone, R. D. Formaldehyde Exposure in Mobile Homes. Master's
Thesis. Seattle: University of Washington, 1978.

31. Cares, J. W. Determination of formaldehyde by the chromotropic
acid method in the presence of oxides of nitrogen. Am. Ind.
Hyg. Assoc. J. 29:405-410, 1968.

32. Carpenter, C. P., and H. F. Smyth, Jr. Chemical burns of the
rabbit cornea. Am. J. Ophthal. 29: 1363-1372, 1946.

33. Casarett, L. J., and J. Doull. Toxicology: The Basic Science
of Poisons, pp. 299, 512, and 513. New York: MacMillan
Publishing Co., Inc., 1975.

34. Chanet, R. , C. Izard, and E. Moustacchi. Genetic effects of
formaldehyde in yeast. I. Influence of the growth stages on
killing and recombination. Mutat. Res. 33:179-186, 1975.

35. Chanet, R. , and R. C. von Borstal. Genetic effects of
formaldehyde in yeast. III. Nuclear and cytoplasmic mutagenic
effects. Mutat. Res. 62:239-253, 1979.

36. Chugh, K. S., p. c. Singhal, and S. S. Baner]ee. Acute tubular
necrosis following intravesical instillation of formalin. Urol.
Int. 32:454-459, 1977.

37. Clive, D., and J. F. S. Spector. Laboratory procedure for
assessing specific locus mutations at the TK locus in cultured
L5178Y mouse lymphoma cells. Mutat. Res. 31:17-29, 1975.

38. Cohen, I. R. , and A. P. Altshuller. 3-Methyl-2-benzothiazolone
hydrazone method for aldehydes in air. Collection efficiencies
and molar absorptivities. Anal. Chem. 38:1418, 1966.

39. Conners, T. A. Effects of drugs on structure, biosynthesis and
catabolism of nucleic acids, proteins, carbohydrates and lipids,
pp. 443-447. In Z. M. Bacq, R. Capek, R. Paoletti, and J.

209

fir Eds. Fundamentals of Biochemical Pharmacology.
d: Pergamon Press, 1971.

R. A., R. A. Jones, L. J. Jenkins, Jr., and J. Siegel.
1 inhalation studies on ammonia, ethylene glycol,
Idehyde, dimethylamine and ethanol. Toxicol. Appl.
acol. 16:646-655, 1970.

r, J. R. , and M. M. Kini. Biochemical aspects of methanol
ning. Biochem. Pharmacol. 11:405-416, 1962.
ey r L. V. The effect of irritant gases upon the rate of
ry activity. J. Ind. Hyg. Toxicol. 24:193-198, 1942.
enden, A. Built-in fumes plague homes. New York Times.
on 3. Business and Finance. May 7, 1978.
, J. J. Comparative action of acetyl-beta-methyl choline
istamine on the respiratory tract in normals, patients with
ever, and subjects with bronchial asthma. J. Clin. Invest.
0-438, 1947.

inn, T. , and A. Rosengren. Effect of different aldehydes on
eal mucosa. Arch. Otolaryngol. 93:496-500, 1971.
, K. A., L. P. Hanrahan, and M. A. Woodbury. Formaldehyde
ure in nonoccupational environments. In press, 1980.

Porta, 6., M. I. Colneghi, and G. Parmiani.
arcinogenicity of hexamethylenetetramine in mice and rats.
Cosmet. Toxicol. 6:707-715, 1968.

eke, D. Digestion of chromosomal proteins in formaldehyde
ed chromatin. Hoppe-Seyler 's Z. Physiol. Chem.
343-1352, 1978.

e, J. Dermal toxicity, pp. 46-59. In Appraisal of the
y of Chemicals in Foods, Drugs and Cosmetics. Topeka,
s: The Association of Food and Drug Officials of the United
s, 1959.

uil, A., G. Bouley, J. Godin, and C. Boudene. Continuous
at ion of low-level doses of formaldehyde: Experimental

on the rat. Eur. J. Toxicol. 9:245-250, 1976. (in French;
sh summary)

S. E. The physiological and toxic actions of
Idehyde. With a report of three cases of poisoning by
lin. N.Y. Med. J. 104:391-392, 1916.

J. L. , Jr. Retention of inhaled formaldehyde,
onaldehyde, and acrolein in the dog. Arch. Environ. Health
9-124, 1972.

J. R. , Jr., and P. M. Hudgins. Dose-dependent
thomimetic and cardioinhibitory effects of acrolein and
Idehyde in the anesthetized rat. Toxicol. Appl. Pharmacol.
8-366, 1974.

berg, L., A. Gustafsson, and U. Lundgvist. Chemically
ed mutation and sterility in barley. Act a Chem. Scand. 10:
94, 1956.
odt, H. J. Formaldehyde and formic acid level in blood and

of people following previous exposure to formaldehyde,
albl. Arbeitsmed. Arbeitsshutz Prophyl. 26:154-158, 1976.

210

56. Elfers, L. A., and S. Hochheiser. Estimation of Atmospheric
Aliphatic-Aldehyde Concentration by Use of Visual Color
Comparator. Raleigh, N.C.: U.S. Department of Health,
Education, and Welfare, Public Health Service, Consumer
Protection and Environmental Health Service, National Air
Pollution Control Administration, 1969.

57. Ely, F. Formaldehyde poisoning. J. Am. Med. Assoc.
54:1140-1141, 1910.

58. Englesberg, E. The mutagenic action of formaldehyde on
bacteria. J. Bacteriol. 63:1-11, 1952.

59. Epstein, S. S., E. Arnold, J. Andrea, W. Bass, and Y. Bishop.
Detection of chemical mutagens by the dominant lethal assay in
the mouse. Toxicol. Appl. Pharmacol. 23:288-325, 1972.

60. Ettinger, I., and M. Jeremias. A study of the health hazards
involved in working with flameproof ed fabric. N.Y. State Dept.
Labor Div. Ind. Hyg. Mon. Rev. 34:25-27, 1955.

61. Fairhall, L. T. Industrial Toxicology. 2nd ed. Baltimore:
Williams & Wilkins, 1957. 483 pp.

62. Fassbinder, W. , U. Frei, and K.-M. Koch. Haemolysis due to
formaldehyde-induced anti-N-like antibodies in haemodialysis
patients. Klin. Wochenschr. 57:673-679, 1979.

63. Fassett, D. W. Aldehydes and acetals, pp. 1959-1989. In F. A.
Patty, Ed. Industrial Hygiene and Toxicology. 2nd rev. ed. D.
W. Fassett and D. D. Irish, Eds. Vol. II. Toxicology. New
York: Interscience Publishers, 1963.

64. Feldman, M. Y. Reactions of nucleic acids and nucleoproteins
with formaldehyde. Prog. Nucleic Acid Res. Mol. Biol. 13:1-49,
1973.

65. Fel'dman, Yu. G. , and T. I. Bonashevskaya. On the effects of
low concentrations of formaldehyde. Hyg. Sanit. 36 (5) :174-180,
1971.

66. Fisher, A. A. Contact Dermatitis. 2nd ed. Philadelphia: Lea
and Febiger. 1973. 448 pp.

67. Frankel, L. S., K. S. McCallum, and L. Collier. Formation of
bis (chloromethyl) ether from formaldehyde and hydrogen chloride.
Environ. Sci. Technol. 8:356-359, 1974.

68. Freeman, H. G., and W. C. Grendon. Formaldehyde detection and
control in the wood industry. For. Prod. J. 21(9):54-57, 1971.

69. Fregert, S. Manual of Contact Dermatitis. Copenhagen:
Munksgaard, 1974. 107 pp.

70. Fregert, S., and H. J. Bandmann. Patch Testing. New York:
Springer Verlag, 1975. 78 pp.

71. Gamble, J. P., A. J. McMichael, T. Williams, and M. Battigelli.
Respiratory function and symptoms: An environmental-
epidemiological study of rubber workers exposed to a
phenol-formaldehyde type resin. Am. Ind. Hyg. Assoc. J.
37:499-513, 1976.

72. Glass, W. I. An outbreak of formaldehyde dermatitis. N. Z.
Med. J. 60:423-427, 1961.

211

73. Gofmekler, V. A. Effect on embryonic development of benzene and
formaldehyde in inhalation experiments. Hyg. Sanit.
33:327-332, 1968.

74. Golden, J. A., J. A. Nadel, and H. A. Boushey. Bronchial
hyper irritability in healthy subjects after exposure to ozone.
Am. Rev. Resp. Dis. 118:287-294, 1978.

75. Goodman, J. I., and T. R. Tephly. A comparison of rat and human
liver formaldehyde dehydrogenase. Biochim. Biophys. Acta
252:489-505, 1971.

76. Gosser, L. B., and B. E. Butterworth. Mutagenicity evaluation
of formaldehyde in the L5178Y mouse lymphoma assay. Wilmington:
E. I. duPont de Nemours & Co., Haskell Laboratory for Toxicology
and Industrial Medicine, 1977. 6 pp.

77. Governor's Task Force on Insulation. Report on U-F Foam
Insulation. Hartford, Conn.: Connecticut Department of
Consumer Protection, 1979.

78. Grant, W. M. Toxicology of the Eye, pp. 502-506. 2nd ed.
Springfield, 111.: Charles C Thomas, 1974.

79. Grossman, L. I. Paresthesia from N2 or N2 substitute. Report
of a case. Oral Surg. Oral Med. Oral Pathol. 45:114-115, 1978.

80. Guseva, V. A. Gonadotropic effect of formaldehyde on male rats
during its simultaneous introduction with air and water. Gig.
Sanit. 37:102-103, 1972.

81. Harris, D. K. Health problems in the manufacture and use of
plastics. Brit. J. Ind. Med. 10:255-268, 1953.

82. Hauser, T. R. Determination of aliphatic aldehydes.
3-Methyl-2-benzothiazolone hydrazone, hydrochloride (MBTH)
method, pp. F-l to F-4. In Selected Methods for the Measurement
of Air Pollutants. DHEW Publication No. 99-AP-ll. Cincinnati:
U.S. Department of Health, Education, and Welfare, Public Health
Service, Consumer Protection and Environmental Health Service,
Interbranch Chemical Advisory Committee, 1969.

83. Heling, B. , Z. Ram, and I. Heling. The root treatment of teeth
with Toxavit. Report of a case. Oral Surg. Oral Med. Oral
Pathol. 43:306-309, 1977.

84. Helwig, H. How safe is formaldehyde? Dtsch. Med. Woch.
102:1612-1613, 1977. (in German)

85. Hendrick, D. J., and D. J. Lane. Formalin asthma in hospital
staff. Brit. Med. J. 1:607-608, 1975.

86. Hendrick, D. J. , and D. J. Lane. Occupational formalin asthma.
Brit. J. Ind. Med. 34:11-18, 1977.

87. Hilgemeier, M. W. Presentation on New Hampshire experiences
with urea-formaldehyde foam, given at Ad Hoc Task Force Seminar
on An Assessment of the Odor Problems from U-F Foam Insulations,
Washington, D.C., December 1, 1978.

88. Hogg, J. C. f P. D. Par 4, and R. C. Boucher. Bronchial mucosal
permeability. Fed. Proc. 38:197-201, 1979.

89. Hollowell, C. D., J. V. Berk, and G. W. Traynor. Impact of
reduced infiltration and ventilation on indoor air quality in
residential buildings. ASHRAE Trans. 85:816-826, 1979.

212

90. Horsfall, p. L. , jr. Formaldehyde hypersensitiveness an
experimental study. J. Immunol. 27:569-581, 1934.

91. Horton, A. W. , R. Tye, and K. L. Steiraner. Experimental
carcinogenesis of the lung. Inhalation of gaseous formaldehyde
or an aerosol of coal tar by C3H mice. J. Nat. Cancer inst.
30:31-43, 1963.

92. HpJvding, G. Occupational dermatitis from pyrolysis products of
polythene. Acta Derm. Venereol. 49:147-149, 1969.

93. Hsie, A. W. , J. p. O'Neill, J. R. San Sebastian, D. B. couch, J.
C. Fuscoe, W. N. C. Sun, P. A. Brimer, R. Machanoff, J. C.
Riddle, N. L. Forbes, and M. H. Hsie. Mutagenicity of
carcinogens: Study of 101 agents in a quantitative mammalian
cell mutation system, CHO/HGPRT. Fed. Proc. 37:1384, 1978.

94. Humpstone, O. p., and W. Lintz. A case of formalin poisoning.
J. Am. Med. Assoc. 52:380-381, 1909.

95. Hurni, H. , and H. Ohder . Reproduction study with formaldehyde
and hexamethylenetetramine in beagle dogs. Food cosmet.
Toxicol. 11:459-462, 1973.

96. Jordan, W. P., Jr., W. T. Sherman, and S. E. King. Threshold
responses in formaldehyde-sensitive subjects. J. Am. Acad.
Dermatol. 1:44-48, 1979.

97. Kallos, G. J., and R. A. Solomon. Investigations of the
formation of bis (chloromethyl) ether in simulated hydrogen
chloride-formaldehyde atmospheric environments. Am. ind. Hyg.
Assoc. J. 34:469-473, 1973.

98. Kane, L. E. , and Y. Alarie. Sensory irritation to formaldehyde
and acrolein during single and repeated exposures in mice. Am.
Ind. Hyg. Assoc. J. 38:509-522, 1977.

99. Karlson, P. Introduction to Modern Biochemistry. 2nd ed.
Chapters 6, 8, 11, and 12. New York: Academic Press, 1965.

100. Kelecom, J. Les brtflures oculaires par le formol. Arch.
Ophthal. (Paris) 22:259-262, 1962.

101. Kendall, A. I. The relaxation of histamine contractions in
smooth muscle by certain aldehydes. Studies in bacterial
metabolism. LXXXIII. J. Infectious Dis. 40:689-698, 1927.

102. Kerfoot, E. J. f and T. F. Mooney, Jr. Formaldehyde and
paraformaldehyde study in funeral homes. Am. Ind. Hyg. Assoc.
J. 36:533-537, 1975.

103. Kitchens, J. F. , R. E. Casner, 6. S. Edwards, W. E. Ha r ward III,
and B. J. Macri. Investigation of Selected potential
Environmental Contaminants: Formaldehyde. U.S. Environmental
Protection Agency Report No. EPA-560/2-76-009. Washington,
D.C.: U.S. Environmental Protection Agency, Office of TOXIC
Substances, 1976. 204 pp.

104. Kligman, A. M. , and W. Epstein. Updating the maximization test
for identifying contact allergens. Contact Dermatitis
1:231-239, 1975.

105. Kline, B. S. Formaldehyd poisoning. With report of a fatal
case. Arch. Intern. Med. 36:220-228, 1925.

106. Koops, A. In vitro Microbial Mutagenicity Studies of
Formaldehyde (37% A. I.). Wilmington, Del.: E. I. du Pont de

213

Nemours and Company, Haskell Laboratory for Toxicology and
Industrial Medicine, 11 March 1976 (unpublished) . 4 pp.

107. Kratochvil, I. The effect of formaldehyde on the health of
workers employed in the production of crease resistant ready
made dresses. Pr. Lek. 23:374-375, 1971. (in Czech; English
abstract)

108. Kuschner, M. , S. Laskin, R. T. Drew, V. Cappiello, and N.
Nelson. Inhalation carcinogenicity of alpha halo ethers. III.
Lifetime and limited period inhalation studies with

bis (chloromethyl) ether at 0.1 ppm. Arch. Environ. Health
30:73-77, 1975.

109. La Du, B. N. , H. G. Mandel, and H. L. Way, Eds. Fundamentals of
Drug Metabolism and Drug Disposition, pp. 169-171, 206-208,
292-294. Baltimore: Williams & Wilkins, 1971.

110. Laffont, H. , and J.-B. Noceto. A case of asthma due to
sensitivity to formaldehyde. Alg4rie Med. 65:777-781, 1961.
(in French)

111. Lam, S., R. Wong, and M. Yeung. Nonspecific bronchial
reactivity in occupational asthma. J. Allerg. Clin. Immunol .
63:28-34, 1979.

112. Leonardos, G., D. Kendall, and N. Barnard. Odor threshold
determinations of 53 odorant chemicals. J. Air Pollut. Control
Assoc. 19:91-95, 1969.

113. Levaggi, D. A., and M. Feldstein. The determination of
formaldehyde, acrolein, and low molecular weight aldehydes in
industrial emissions on a single collection sample. J. Air
Pollut. Control Assoc. 20:312-313, 1970.

114. Levison, L. A. A case of fatal formaldehyde poisoning. J. Am.
Med. Assoc. 42:1492, 1904.

115. Logan, W. S., and H. 0. Perry. Contact dermatitis to
resin-containing casts. Clin. Orthop. Relat. Res. 90:150-152,
1973.

116. Lyles, G. R. , F. B. Dowling, and V. J. Blanchard. Quantitative
determination of formaldehyde in the parts per hundred million
concentration level. J. Air Pollut. Control Assoc. 15:106-108,
1965.

117. Magana-Schwencke, N., B. Ekert, and E. Moustacchi. Biochemical
analysis of damage induced in yeast by formaldehyde. I.
Induction of single-strand breaks in DNA and their repair.
Mutat. Res. 50:181-193, 1978.

118. Magana-Schwencke, N., and E. Moustacchi. Biochemical analysis
of damage induced in yeast by formaldehyde. III. Repair of
induced cross-links between DNA and proteins in the wild-type
and in excision-deficient strains. Mutat. Res. 70:29-35, 1980.

119. Magnusson, B., and A.M. Kligman. usefulness of guinea pig tests
for detection of contact sensitizers, pp. 551-560. In F. N.
Marzulli and H. I. Mai bach, Eds. Advances in Modern
Toxicology. Vol. 4. Dermatotoxicology and Pharmacology.
Washington, D.C.: Hemisphere Publishing Corporation, 1977.

214

120. Manna, G. K., and B. B. Panda. Formalin induced sex chromosome
breakage in the spermatocyte cells of the grasshopper, Tristria
pulvinata. J. Cytol. Genet. 2:86-91, 1967.

121. Mant, M. J. , T. Connolly, P. A. Gordon, and E. G. King. Severe
thrombocytopenia probably due to acute folic acid deficiency.
Grit. Care Med. 7:297-300, 1979.

122. March, G. H. Formalin poisoning; recovery. Br. Med. J. 2:687,
1927.

123. Marks, T. A., W. C. Worthy, and R. E. Staples. Influence of
Formaldehyde and Sonacide (Potentiated Acid Glutaraldehyde)
on Embryo and Fetal Development in Mice. Research Triangle
Park, N.C.: Research Triangle Institute, 1980. (in press)

124. Martin-Amat, G., K. E. McMartin, S. S. Hay r eh, M. S. Hay r eh, and
T. R. Tephly. Methanol poisoning. Ocular toxic ity produced by
formate. Toxicol. Appl. Pharmacol. 45:201-208, 1978.

125. Marzulli, F., T. R. Carson, and H. I. Maibach. Delayed contact
hypersensitivity studies in man and animals, pp. 107-122. in
Proceedings. Joint Conference on Cosmetic Sciences. Washington,
D.C., April 21-23, 1968. Washington, D.C.: The Toilet Goods
Association, Inc., 1968.

126. Marzulli, F. N. , and H. I. Maibach. Antimicrobials:
Experimental contact sensitization in man. J. Soc. Cosmet.
Chem. 24:399-421, 1973.

127. Marzulli, F. N., and H. I. Maibach. The use of graded
concentrations in studying skin sensitizers: Experimental
contact sensitization in man. Food Cosmet. Toxicol. 12:219-227,
1974.

128. Matoth, Y., I. Zehavi, E. Topper, and T. Klein. Folate

nutrition and growth in infancy. Arch. Dis. Childhood
54:699-702, 1979.

129. McMartin, K. E. , J. J. Ambre, and T. R. Tephly. Methanol
poisoning in human subjects. Role for formic acid accumulation
in the metabolic acidosis. Am. J. Med. 68:414-418, 1980.

130. McMartin, K. E. , G. Martin-Amat, A. B. Makar, and T. R. Tephly.
Methanol poisoning. V. Role of formate metabolism in the
monkey. J. Pharmacol. Exp. Therap. 201:564-572, 1977.

131. McMartin, K. E. , G. Martin-Amat, P. E. Noker, and T. R. Tephly.
Lack of a role for formaldehyde in methanol poisoning in the
monkey. Biochem. Pharmacol. 28:645-649, 1979.

132. Melekhina, V. P. Hygienic evaluation of formaldehyde as an
atmospheric air pollutant, pp. 9-18. In B. S. Levine, Ed.
U.S.S.R. Literature on Air Pollution and Related Occupational
Diseases. Vol. 9. A Survey. Washington, D.C.: U.S. Public
Health Service, 1963-1964. (available from National Technical
Information Service, Springfield, Va., as TT64-11574)

133. Miller, B. H. , and H. P. Blejer. Report of an Occupational
Health Study of Formaldehyde Concentrations at Maximes, 400 E.
Colorado Street, Pasadena, California. Study No. S-1838. Los
Angeles: State of California Health and Welfare Agency,
Department of Public Health, Bureau of Occupational Health,
1966. 5 pp.

215

134. Mills, J. CPSC warns about health hazard of foam home material.
Washington Post, Real Estate, August 11, 1979.

135. Montgomery, S. Paresthesia following endodontic treatment. J.
Endodon. 2:345-347, 1976.

136. Morgan, G. B., C. Golden, and E. C. Tabor. New and improved
procedures for gas sampling and analysis in the National Air
Sampling Network. J. Air Pollut. Contr. Assoc. 17:300-304, 1967,

137. Morrill, E. E., Jr. Formaldehyde exposure from paper process
solved by air sampling and current studies. Air Cond. Heat.
Vent. 58(7):94-95, 1961.

138. Nagorny, P. A., Z. A. Sudakova, and S. M. Schablenko. On the
general toxic and allergic action of formaldehyde. Gig. Tr.
Prof. Zabol. 1:27-30, 1979.

139. National Research Council, Committee on Toxicology.
Formaldehyde. An Assessment of Its Health Effects. Washington,
D.C.: National Academy of Sciences, 1980. 38 pp.

140. National Research Council, Panel on Air Quality in Manned
Spacecraft. Atmospheric Contaminants in Spacecraft.
Washington, D.C.: National Academy of Sciences, 1972. 11 pp.

141. Neely, W. B. The metabolic fate of formaldehyde- 14 C
intraperitoneally administered to the rat. Biochem. Pharmacol.
13:1137-1142, 1964.

142. North American Contact Dermatitis Group. Epidemiology of
contact dermatitis in North America: 1972. Arch. Dermatol.
108:537-540, 1973.

143. Nova, H. , and R. G. Touraine. Asthma from formaldehyde. Arch.
Mai. Prof. 18:293-294, 1957. (in French)

144. Odom, R. B., and H. I. Maibach. Chapter 15. Contact
urticaria: A different contact dermatitis, pp. 441-453. In F.
N. Marzulli and H. I. Maibach, Eds. Advances in Modern
Toxicology. Vol. 4. Derma to toxicology and Pharmacology.
Washington, B.C.: Hemisphere Publishing Corporation, 1977.

145. Orringer, E. P., and w. D. Mattern. Formaldehyde-induced
hemolysis during chronic hemodialysis. New Eng. J. Med.
294:1416-1420, 1976.

146. Palecek, E. Premelting changes in DNA conformation. Prog.
Nucleic Acid Res. Mol. Biol. 18:151-213, 1976.

147. Palese, M. , and T. R. Tephly. Metabolism of formate in the
rat. J. Toxicol. Environ. Health 1:13-24, 1975.

148. Paliard, F., L. Roche, C. Exbrayat, and E. Sprunck. Chronic
asthma due to formaldehyde. Arch. Mai. Prof. 10:528-530, 1949.

(in French)

149. Parker, C. D., R. E. Bilbo, and C. E. Reed. Methacholine
aerosol as test for bronchial asthma. Arch. Intern. Med.
115:452-458, 1965.

150. Pepys, J., C. A. C. Pickering, A. B. X. Breslin, and D. J.
Terry. Asthma due to inhaled chemical agents tolylene
di-isocyanate. Clin. Allergy 2:225-236 , 1972.

151. Popa, V., D. Teculescu, D. Stanescu, and N. Gavrilescu.
Bronchial asthma and asthmatic bronchitis determined by simple
chemicals. Dis. Chest 56:395-404, 1969.

216

152. Porter, J. A. H. Acute respiratory distress following formalin
inhalation. Lancet 2:603-604, 1975.

153. Potts, A. M. , J. Praglin, I. Farkas, L. Orbison, and D.
Chickering. Studies on the visual toxicity of methanol. VIII.
Additional observations on methanol poisoning in the primate
test object. Am. J. Ophthalmol. 40(5, Pt. II):76-83, 1955.

154. Proctor, D. F. The upper airways. I. Nasal physiology and
defense of the lungs. Am. Rev. Resp. Dis. 115:97-129, 1977.

155. Pruett, J. J., H. Scheuenstuhl, and D. Michaeli. The
incorporation and localization of aldehydes (highly reactive
cigarette smoke components) into cellular fractions of cultured
human lung cells. Arch. Environ. Health 35:15-20, 1980.

156. Rapoport, I. A. Mutations under the influence of unsaturated
aldehydes. Doklady Akad. Nauk S.S.S.R. 61:713-715, 1948. (in
Russian)

157. Rathery, F. , R. Piedelievre, and J. Delarue. Death by
absorption of formalin. Ann. Med. Leg. Criminol. 20:201-206,
1940. (in French)

158. Rayner, A. C. , and C. M. Jephcott. Microdetermination of
formaldehyde in air. Anal. Chem. 33:627-630, 1961.

159. Renzetti, N. A., and R. J. Bryan. Atmospheric sampling for
aldehydes and eye irritation in Los Angeles smog 1960. J. Air
Pollut. Control Assoc. 11:421-424, 427, 1961.

160. Rietbrock, N. Kinetics and pathways of methanol metabolism.
Naunyn-Schmeidebergs Arch. Pharmakol. Exper. Pathol. 263:88-105,
1969. (in German)

161. Rostenberg, A., Jr., B. Bairstow, and T. W. Luther. A study of
eczematous sensitivity to formaldehyde. J. Invest. Dermatol.
19:459-462, 1952.

162. Roth, W. G. Tylosic palmar and plantar eczema caused by
steaming clothes containing formalin. Berufsdermatosen
17:263-268, 1969.

163. Rumack, B. Position Paper. Urea-Formaldehyde Foam. Denver:
Rocky Mountain Poison Center, 1978. 22 pp.

164. Sakula, A. Formalin asthma in hospital laboratory staff.
Lancet 2:816, 1975.

165. Sasaki, Y., and R. Endo. Mutagenicity of aldehydes in
Salmonella. Abstract No. 27. Mutat. Res. 54:251-252, 1978.

166. Sawicki, E., and R. A. Carnes. Spectrophotofluorimetric
determination of aldehydes with dimedone and other reagents .
Mikrochim. Acta 1968:148-159, 1968.

167. Schoenberg, J. B., and C. A. Mitchell. Airway disease caused by
phenolic (phenol-formaldehyde) resin exposure. Arch. Environ.
Health 30:574-577, 1975.

168. Schuck, E. A., E. R. Stephens, and J. T. Middleton. Eye
irritation response at low concentrations of irritants. Arch.
Environ. Health 13:570-575, 1966.

169. Sellakumar, A. R. , R. E. Albert, G. M. Rusch, G. V. Katz, N.
Nelson, and M. Kuschner. Inhalation carcinogenicity of
formaldehyde and hydrogen chloride in rats. Abstr. No. 424.
Am. Assoc. Can. Res. Proc. 21:106, 1980.

217

170. Shapira, Y., A. Ben Zvi, and M. Statter. Folic acid
deficiency: A reversible cause of infantile hypotonia. J. Fed.
93:984-986, 1978.

171. Sheveleva, G. A. Investigation of the specific effect of
formaldehyde on the embryogenesis and progeny of white rats.
Toksikol. Novykh Prom. Khim. Veschestv 12:78-86, 1971.

172. Shikama, K., and K. I. Miura. Equilibrium studies on the
formaldehyde reaction with native DMA. Eur. J. Biochem.
63:39-46, 1976.

173. Shipkovitz , H. D. Formaldehyde Vapor Emissions in the
Permanent-Press Fabrics Industry. Report No. TR-52.
Cincinnati: U.S. Department of Health, Education, and Welfare,
Public Health Service, Consumer Protection and Environmental
Health Service, Environmental Control Administration, 1968. 18
pp.

174. Shumilina, A. V. Menstrual and child-bearing functions of female
workers having contact with formaldehyde under factory
conditions. Gig. Trud. Prof. Zabol. 12:18-21, 1975.

175. Sim, V. M. , and R. E. Pattle. Effect of possible smog irritants
on human subjects. J. Am. Med. Assoc. 165:1908-1913, 1957.

176. Smith, A. B. , S. M. Brooks, J. Blanchard, I. L. Bernstein, and
J. Gallagher. Absence of airway hyper reactivity to methacholine
in a worker sensitized to toluene diisocyanate (TDI). J. Occup.
Med. 22: 327-331, 1980.

177. Smith, R. G., R. J. Bryan, M. Feldstein, B. Levadie, F. A.
Miller, E. R. Stephens, and N. G. White. Tentative method of
analysis for formaldehyde content of the atmosphere (MBTH,
colorimetric method, applications to other aldehydes). Health
Lab. Sci. 7(3):173-178, 1970.

178. Smith, R. G. , R. J. Bryan, M. Feldstein, B. Levadie, F. A.
Miller, E. R. Stephens, and N. G. White. Tentative method of
analysis for low molecular weight aliphatic aldehydes in the
atmosphere. Health Lab. Sci. 9(l):75-78, 1972.

179. Smyth, H. F. , Jr., J. Seaton, and L. Fischer. The single dose
toxicity of some glycols and derivatives. J. Ind. Hyg. Toxicol.
23:259-268, 1941.

180. Sneddon, I. B. Dermatitis in an intermittent haemodialysis
unit. Brit. Med. J. 1:183-184, 1968.

181. Solyanik, R. G., Yu. V. Federov, and I. A. Rapoport. The
mutagenic effect of some alkylating compounds on eastern equine
encephalomyelitis virus. Sov. Genet. 8:412-413, 1972.

182. Spector, S. L. , and R. S. Farr. A comparison of methacholine
and histamine inhalations in asthmatics. J. Allergy Clin.
Immunol. 56:308-316, 1975.

183. Stickney, R. N. Engineering, Safety, and Control for the Proper
Handling of Formaldehyde. Presented at the Formaldehyde Seminar
and Plant Tour held by the Borden Chemical Company,
Fayetteville, N.C., March 11, 1958.

184. Strittmatter, P., and E. G. Ball. Formaldehyde dehydrogenase, a
glutathione-dependent enzyme system. J. Biol. Chem.
213:445-461, 1955.

218

185. Swenberg, J. A. , W. D. Kerns, R. I. Mitchell, E. J. Gralla, and
K. L. Pavkov. Induction of squamous cell carcinomas of the rat
nasal cavity by inhalation exposure to formaldehyde vapor.
Cancer Res. 40:3398-3402, 1980.

186. Tabershaw, I. R. , H. N. Doyle, L. Gaudette, S. H. Lamm, and 0.
Wong. A Review of the Formaldehyde Problems in Mobile Homes.
Rockville, Md.: Tabershaw Occupational Medicine Associates,

P. A., for National Particleboard Association, 1979. 19 pp.

187. Tani, T., S. Satoh, and Y. Horiguchi. The vasodilator action of
formaldehyde in dogs. Toxicol. Appl. Pharmacol. 43:493-499,
1978.

188. Thomas, J. P., E. N. Sanborn, M. Mukai, and B. D. Tebbens.
Identification of aldehydes in polluted atmospheres and
combustion products. A.M. A. Arch. Ind. Health 20:420-428, 1959.

189. Tou, J. C., and G. J. Kallos. Study of aqueous HC1 and
formaldehyde mixtures for formation of bis (chloromethyl)
ether. Am. Ind. Hyg. Assoc. J. 35:419-422, 1974.

190. Townley, R. G., A. K. Bewtra, N. M. Nair, F. D. Brodkey, G. D.
Watt, and K. M. Burke. Methacholine inhalation challenge
studies. J. Allergy Clin. Immunol. 64:569-574, 1979.

191. Tran, N. , M. Laplante, and E. Lebel. Abnormal oxidation of
14 C-formaldehyde to CC>2 in erythrocytes of alcoholics

and nonalcoholics after consumption of alcoholic beverages. J.
Nucl. Med. 13:677-680, 1972.

192. Traynor, G. W. , D. W. Anthon, and C. D. Hollowell. Indoor air
quality: Gas stove emissions, p. 24. In Building ventilation
and indoor air quality program. Chapter fom J. Kessel, Ed.
Energy and Environment Division Annual Report 1978. Lawrence
Berkeley Laboratory Report LBL-9284/EEB-Vent 79-6. Berkeley,
Cal.: Lawrence Berkeley Laboratory, 1979.

193. Tsuchiya, K., Y. Hayashi, M. Onodera, and T. Hasegawa. Toxic ity
of formaldehyde in experimental animals. Concentrations of the
chemical in the elution from dishes of formaldehyde resin in
some vegetables. Keio J. Med. 24:19-37, 1975.

194. Turiar, C. Asthma through sensitivity to formaldehyde. Soc.
Franc. d'Allergie, Seance du 18 Nov. 1952.

195. U.S. Consumer Product Safety Commission. CPSC issues consumer
advisory on formaldehyde insulation. In News from CPSC.
Washington, D.C.: U.S. Consumer Product Safety Commission,
August 1, 1979.

196. U.S. Consumer Product Safety Commission, Directorate for Hazard
Identification and Analysis Epidemiology. Summaries of
in-depth investigations, newspaper clippings, consumer
complaints and state reports on urea-formaldehyde foam home
insulation. Washington, D.C.: U.S. Consumer Product Safety
Commission, July 1978.

197. U.S. Consumer Product Safety Commission. Urea-formaldehyde foam
insulation; Proposed notice to purchasers. Fed. Reg. 45:33946,
1980.

198. U.S. Department of Health, Education, and Welfare, Public Health
Service, Center for Disease Control, National Institute for

219

Occupational Safety and Health. Criteria for a Recommended
Standard. Occupational Exposure to Formaldehyde. DHEW (NIOSH
Publication No. 77-126. Washington, D.C: U.S. Government
Printing Office, 1976. 165 pp.

199. U. S. Department of Health, Education, and Welfare, Public
Health Service, Center for Disease Control, National Institute
for Occupational Safety and Health. Criteria for a Recommended
Standard. . .Occupational Exposure to Inorganic Nickel. DHEW
(NIOSH) Publication No. 77-164. Washington, B.C.: U.S.
Government Printing Office, 1977.

200. U.S. Department of Health, Education, and Welfare, Public Heall
Service, National Institutes of Health. Chronic obstructive
lung diseases, pp. 84-91. In Respiratory Diseases. Task Force
Report on Prevention, Control, Education. DHEW Publication No
(NIH)77-1248. Washington, D.C.: U.S. Government Printing
Office, 1977.

201. U.S. Food and Drug Administration, Bureau of Foods, Division o
Cosmetics Technology. FDA cosmetics data file of voluntary
formulation registration. October 1979.

202. Uotila, L., and M. Koivusalo. Formaldehyde dehydrogenase from
human liver. J. Biol. Chem. 249:7653-7663, 1974.

203. Van Dijken, J. P., R. Otto, and W. Harder. Oxidation of
methanol, formaldehyde and formate by catalase purified from
methanol-grown Hansenula polymorpha. Arch. Microbiol.
106:221-226, 1975.

204. Vaughan, W. T. The Practice of Allergy, p. 677. St. Louis:
The C. V. Mosby Company, 1939.

205. Volfova, 0. Studies on methanol-oxidizing yeast. III. Enzyme.
Folia Microbiol. 20:307-319, 1975.

206. von Wartburg, J. P., and P. M. Schurch. Atypical human liver
alcohol dehydrogenase. Ann. N. Y. Acad. Sci. 151:936-946, 196

207. Walker, J. F. Formaldehyde, pp. 77-99. In A. Standen, Ed.
Kirk-Othmer Encyclopedia of Chemical Technology. 2nd rev. ed.
Vol. 10. New York: Wiley-Interscience Publishers, 1966.

208. Watanabe, F. , T. Matsunaga, T. Soejima, and Y. Iwata. Study o
the carcinogenicity of aldehyde. I. Experimentally produced ra
sarcomas by repeated injections of aqueous solution of
formaldehyde. GANN 45:451-452, 1954. (in Japanese)

209. Waydhas, C., K. Weigl, and H. Sies. The disposition of
formaldehyde and formate arising from drug N-demethylations
dependent on cytochrome P-450 in hepatocytes and in perfused r
liver. Eur. J. Biochem. 89:143-150, 1978.

210. Wayne, L. G., R. J. Bryan, and K. Ziedman. Irritant Effects o
Industrial Chemicals: Formaldehyde. DHEW (NIOSH) Publication
No. 77-117. Washington, D.C.: U.S. Government Printing Office
1976. [138] pp.

211. Wisconsin Division of Health, Bureau of Prevention.
Formaldehyde Case File Summary. October 23, 1978. Madison,
Wis.: Wisconsin Division of Health, 1978. 3 pp.

220

212. Wisconsin Division of Health, Bureau of Prevention. Statistics
of Particle Board Related Formaldehyde Cases through December
15, 1978. Madison, Wis.: Wisconsin Division of Health, 1978. 4
pp.

213. Woodbury, J. W. . Asthmatic syndrome following exposure to
tolylene diisocyanate. Ind. Med. Surg. 25:540-543, 1956.

214. Woodbury, M. A., and C. Zenz. Formaldehyde in the home
environment. Prenatal and infant exposure. In press, 1980.

215. Yefremov, G. G. The state of the upper respiratory tract in
formaldehyde production employees. Zh. Ushn. Nos. Gorl. Bolezn.
30: 11-15, 1970. (in Russian)

216. Yunghans, R. S., and W. A. Monroe. Continuous monitoring of
ambient atmospheres with the Technicon AutoAnalyzer , pp.
279-284. In Automation in Analytical Chemistry. Technicon
Symposia 1965. Vol. I. New York: Mediad, Inc., 1966.

217. Zaeva, G. N. , I. P. Ulanova, and L. A. Dueva. Materials for
revision of the maximal permissible concentrations of
formaldehyde in the inside atmosphere of industrial premises.
Gig. Tr. Prof. Zabol. 12:16-20, 1968. (in Russian)

218. Zannini, D. , and L. Russo. Long-standing lesions in the
respiratory tract following acute poisoning with irritating
gases. Lav. Urn. 9:241-254, 1957. (in Italian; English summary)

CHAPTER 8
HEALTH EFFECTS OF SOME OTHER ALDEHYDES

This chapter discusses the effects of aldehydes other than
formaldehyde on biologic preparations/ animals, and man. It
represents an extensive review of the available published information
to assess the health effects of aldehydes on humans and animals.

TOXICITY OF ALDEHYDES OTHER THAN FORMALDEHYDE

The total of occupational exposures to aldehydes in 1976 is shown
in Table 8-1. Direct evidence of the human health effects of
aldehydes is related predominantly to eye irritation, olf action
threshold, and irritation of the upper respiratory tract and skin. T
a lesser degree, isolated human biochemical reactions have been
monitored.

Toxicity information obtained from animal studies for common
aliphatic and aromatic aldehydes is summarized in Tables 8-2, 8-3, an
8-4. The major pathophysiologic effects of aldehydes 31 are
described briefly below.

IRRITATION OF THE SKIN, EYES, AND RESPIRATORY MUCOSA

Irritancy is a property of nearly all the aldehydes, but it occur
more commonly and is more important in the case of those with lower
molecular weights and those with unsaturation in the aliphatic chain
or with halogenated substituents. The general and parenteral toxicit
of these compounds appears to be related primarily to irritation,
although in some cases (such as fluoroacetaldehyde or fluorobutanal)
metabolic conversion to the corresponding fluorinated acids produces
an extraordinarily high degree of toxicity. The irritant properties
of the dialdehydes have not been extensively studied, but in some
instances concentrated solutions can severely irritate the skin and
the eyes. The acetals and the aromatic aldehydes in general have a
lower degree of irritant action, although there are some exceptions.
Furfural has irritant properties, but is not nearly as active as
acrolein. 3 l

221

222

TABLE 8-1

Occupational Exposures to Aldehydes 3

Aldehyde No. Exposures

Acet aldehyde 1,744

Acrolein 7,301

Benzaldehyde 15,985

n-Butyraldehyde 1,259

Furfural 15,412

Glutar aldehyde 35,083

Glyoxal 3,848

Propionaldehyde 1,544

a Data from NIOSH. 111

<g u
u *4

3S

4J q

a a

CO

tt)
-a

u o 01 o

sag !

CN
I

00

3

a)

4J

cd
M

4J

cd

03

4-1
O

H
O
H
X
O
H

o

A

o\

HIM

01

u

4J B

a

U 0.

n

01

u

g o

g

3 o

I

X i

iH

O

IN

r-J
01

3

U

01

Severe

rt

S3
1

S
3
2

Sever

J3

rH

rt

u

01

O

o

01

Hoderal

a
s

d

i

Moderal

us

ON

s

81

o

o

II O

ft

as

3 oo"

3d"

4

n

1

j=

a
u

o

<f

m

*

** ^o

a

3

u

3

4J

S

u

u

1

1

%

n

-I

So
S

u

S

OO

m

en

0)

?,

01 ,-N

01

1

8

3

a f-i
^

<B

a

ffl

3

&

1-)

2 S

6

J

i

U 01

u

o

3 a.

3

a

M

a

u

"V,

S 3

3'u

II

223

8 9

H

th

I U

q) -H
U U

O U

a -H

rt U
U -H GM>

^

S3

CX

CO

0)
13

&

^

oJ

13

3

i?

S"

U Ptf

01

CJ

IW

H

CT,

rt

a

s a 1

U Ml 3

0)

H

TJ

0)

CO

i |

R ca

01

1

^J

H

00

en

13

en

w

0)

31

3

I-J

U

2

cd

ml

*

H

3

cd

r-

D

p CT4

SJ o S

et o *

" S

U-l

o

J -

a

O

4J

g d

H

3 ^ a 1
3 sl 1

.d

$
O

1 H s

^M

"*

H

B
H

224

fx. VO

en CM

CO

cu

T3

I

id

I

00

o

H

4-1

S
O

X

w <a

O
H

25. i'

1-1 3 gj O
3 S.H J3

vo

" 8

S m

r i

!

3

^ <" a

I U -O -H

Sf.'

3^

(8 M

225

226

SENSITIZATION

Direct sensitization to aldehyde vapors appears to be relatively
rare, and sensitization to addition products, such as the bisulfites,
almost never occurs. Because of the bifunctional nature of the
dialdehydes, they should theoretically be capable of acting as skin
sensitizers, but there have been few reports of this phenomenon. 31

Sensitization to the unsaturated aldehydes may occur, but it is
usually very difficult to separate the primary irritation from
sensitization. Skin sensitization to the acetals and aromatic
aldehydes appears to be infrequent. Pulmonary sensitization and
asthma-like symptoms are rarely caused by the inhalation of
aldehydes. 3 1

ANESTHESIA

Chloral hydrate and paraldehyde have unquestionable anesthetic
properties. The former may act through its metabolism to
trichloroethanol, and the latter by depolymerization to acetaldehyde.
When administered experimentally in large parenteral or oral doses, a
number of the aliphatic aldehydes produce anesthesia-like symptoms.
However, in industrial exposures, this action is minimized because the
primary irritant action prevents substantial voluntary inhalation. In
addition, the small quantities that can be tolerated by inhalation are
usually metabolized so rapidly that no anesthetic symptoms occur.
Some nausea, vomiting, headache, and weakness have been reported in
chemists exposed to high concentrations of isovaleraldehyde, but these
symptoms have not been interpreted as definite anesthetic
reactions. 3 x

ORGAN PATHOLOGY

The principal pathologic conditions produced in animals exposed to
aldehyde vapors are damage to the respiratory tract and pulmonary
edema, in general, multiple hemorrhages and alveolar exudate may be
present, but are usually much less apparent than with gases like
phosgene. The effects produced by ketene, acrolein, crotonaldehyde,
and chloracetaldehyde are much more pronounced and similar to those of
phosgene, and chlorine. High dosages of methylal and furfural have
been reported to cause various changes in the liver, kidneys, and
central nervous system, but there has been no confirmation of this
type of action in human industrial exposures. The aldehydes are
remarkably free of effects that lead to definite cumulative damage to
tissues other than effects that may be associated with primary
irritation or sensitization. 91

227
METABOLISM AND MECHANISM OF IRRITATION

The simple aliphatic aldehydes are oxidized to their corresponding
fatty acids, which normally undergo fl-oxidation. Urinary metabolites
are not generally detectable, because the fatty acids are further
oxidized to carbon dioxide and water. Acetaldehyde is present in
normal metabolism, and its importance as a metabolite of ethanol is
well known. In general, the toxicity of aldehydes appears to decrease
with increasing molecular weight. This relationship is shown by both
the oral LD^Q and the primary irritant action of the lower-
molecular-weight substances, which makes them appear to be more
potent. 31 As shown in Table 8-5, some of the higher aldehydes are
less toxic than their corresponding alcohols, but the unsaturated
aldehydes are more toxic than corresponding saturated ones. Although
primary irritation and contact dermatitis are occasionally seen after
occupational exposure to aldehydes, there is no evidence of serious
cumulative effects.

Evidence from a human chamber-exposure study indicated that
unsaturation greatly increases the primary irritant activity of an
aldehyde (Table 8-6). Halogen substitution in aldehydes may also
greatly increase the local tissue irritation. 31 Dixon 22 has
postulated that the presence of an aldehyde group adjacent to a double
bond has a polarizing effect on the latter, which makes the double
bond capable of adding nucleophilic groups, such as sulfhydryl
groups. If the sulfhydryl groups in enzymes found in nerve endings
are attacked, it seems reasonable that this might be related to the
physiologic response of lacrimation. There are, however, difficulties
with this explanation, as pointed out by Dixon. 22 The lacrimatory
action of such materials is usually very transient and ceases
immediately on removal of the irritant. Dixon speculated that the
nerve endings may respond to a change in the relative amount of the
sulfhydryl compound present, but further evidence seems necessary on
this point, it is interesting that, if exposure to a lacrimator is
sufficiently prolonged, a point is reached at which lacrimation no
longer occurs; this suggests complete saturation of some reactive
site. 31

The primary irritation is probably associated with the reactivity
of aldehydes with proteins and amino acids. For example, methylol or
hydroxymethyl derivatives may be formed from reaction of aliphatic
aldehydes with amino groups.

Cyclic compounds may be formed through later reactions. In the
case of the aromatic aldehydes, the products of reaction with amino
groups appear to be Schif f bases (C 6 H 5 CH=N-R) . Various types of
cross-linking reactions can also occur with either aldehydes or
dialdehydes, resulting in alteration in protein structures. 31

The aromatic aldehydes are oxidized to their corresponding organic
acids. The oxidation occurs relatively slowly in the liver, but it is
usually complete, except where such substituents as hydroxy groups
make the aldehydes capable of being excreted by alternative metabolic
pathways, such as sulfate or glucuronic acid conjugations. 31

228

TABLE 8-5
Oral Toxicities of Corresponding Alcohols, Aldehydes, and Acids'

Oral LD qn in Rats, g/kg

RCH 9

Alcohol,"
RCH 9 OH

Aldehyde ,
RCHO

Acid,
RCOOH

3

Ethyl

9-10

1.93

3.53

H 5

Propyl

1.87

1.41

2 :CH

Acrylyl

0.064

0.046

2.52

C 3 H 7

Butyl

4.36

5.89

8.79

3 CH:CH

Crotonyl

0.3

1.0

C 5 H 11

iso-Butyl

2.46
4.59

3.73
4.89

6.44

Hexyl

2 H 5 ) 2 CH

2-Ethylbutyl

1.85

3.98

2.20

CAH 9 (C 2 H 5 )CH

2-Ethylhexyl

3.20

3.73

3.00

leprinted with permission from Williams.

229

TABLE 8-6

Results of Human Exposure to Aldehydes in a Chamber'

Aldehyde
Acrolein

Crotonaldehyde

Ace t aldehyde
Propionaldehyde
Butyr aldehyde
Isobutyr aldehyde

Chamber

Concentration,

ppm

0.80

1.22

4.1

134
134
230
207

Duration of

Exposure,

min

10

15

30
30
10
30

Symptoms

Extremely irritatir
lacrimatory (20 s

Extremely irritatii
lacrimatory (5s

Highly irritating <=
lacrimatory (30 i

Slightly irritating
Nonirritating
Nonirritating
Nonirritating

a Data from Sim and Pattle. 96
Average time after exposure at which lacrimation occurred.

230

Aldehydes occur naturally in foods and have been used extensively
as flavoring agents. The rapid metabolism of the aliphatic and
aromatic aldehydes by normal pathways undoubtedly accounts for the
apparent safety of the large number of these substances that are
ingested by humans and animals.

Several aldehydes such as those listed in Table Q,-7 have been
shown to have antineoplastic activity. 87

It has been demonstrated that several environmental irritants are
ciliotoxic and mucus-coagulating agents. Aldehydes may thus
facilitate the uptake of other airborne substances by the bronchial
epithelium.

ACETALDEHYDE

Acetaldehyde is much less irritating to the human eye, nose, and
throat than formaldehyde or acrolein. Animal studies have shown
acetaldehyde to have low acute toxicity and no appreciable cumulative
effects. It does not appear to have substantial mutagenic effects,
but has been shown, in a single study, to have dose-dependent
embryotoxic and teratogenic properties. Its carcinogenic potential
has not been adequately studied. A major source of acetaldehyde in
man is the metabolism of ethanol.

ACETALDEHYDE IN ANIMALS
Acute Toxicity

By the acute oral route of administration, acetaldehyde is
slightly toxic, with reported LD5Q values in rats of 1,930
rag/kg 71 * and 5,300 mg/kg. 70 Its effect on the skin and eyes of
laboratory animals has not been investigated. Human occupational
exposure has shown that contact of the eye or skin with liquid
acetaldehyde can produce painful, but not serious, burns. 61 6I * The
rapid evaporation of the liquid limits the duration of the
contact. 61 * Acetaldehyde appears to act as an anesthetic in acute
inhalation exposures at high concentrations. When exposed at 20,000
ppm, rats became anesthetized after a brief period of pronounced
excitement. Half the animals died after 30 mm of exposure; pulmonary
edema was the principal pathologic finding. The survivors recovered
in about an hour. 97 In other laboratory animals (mice, rabbits, and
guinea pigs) , acetaldehyde is slightly to moderately toxic, with
calculated 4-h LC5Q values of approximately 1,100 ppm. 83
Subcutaneous-injection studies in rats and mice produced lethal
effects at 500-600 mg/kg. 9

Aldehyde
Glyoxal

Methylglyoxal
Kethoxal

231

TABLE 8-7
An tineo plastic Activity of Aldehydes 3

Active Against

Leukemia L 1210

Sarcoma-180

Sarcoma-180

Leukemia L 1210

Sarcoma-180

Walker-256

Leukemia L 1210
Sarcoma-180
Walker-25b
Jensen sarcoma
Lymphosarcoma

1,4- and 1,5-dicarbonylaldehyde

Polyaldehydes

Pyridin-2-carboxaldehyde

Isoquinolin-1-carboxaldehyde

Benzaldehyde N-mustards

Salicylaldehyde and other aromatic aldehydes

Sarcoma-180
Sarcoma-180

Leukemia L 1210
Sarcoma-180
Levis-King carcinoma

Leukemia L 1210
Sarcoma-180
Levis-King carcinoma

Leukemia L 1210
Walker-25b
Dunnung leukemia

Leukemia L 1210

a Data from Schauenstein et al.

87

232
Extended Studies

In chronic and subchronic oral studies, acetaldehyde has not
produced major toxic effects. In a 6-wk subchronic study/ no adverse
effects on behavior, weight, or condition of the blood were observed
in groups of 10 rats given 550 or 1,100 mg/kg per day. Pathologic
examination revealed a statistically significant increase in glycogen
content of the liver in the 550-mg/kg group, but not in the
1,100-mg/kg group. Histopathologic examination of the liver revealed
nonspecific inflammatory and dys trophic changes. A 6-mo oral study
revealed no adverse effects on behavior or weight in groups of 10 rats
given up to 50 mg/kg per day. Minimal changes in ECG pattern and
blood morphology were reported. These effects were reversible; all
animals returned to normal within a month. 70

In one inhalation study, groups of 20 hamsters were exposed to
acetaldehyde at 390, 1,340, or 4,560 ppm, 6 h/d, 5 d/wk for 18 wk.
The highest concentration induced growth retardation, ocular and nasal
irritation, increased numbers of erythrocytes in the blood, increased
heart and kidney weights, and severe histopathologic changes in the
respiratory tract. The latter consisted of inflammatory changes,
hyperplasia, metaplasia, and necrosis of the respiratory epithelium.
The upper respiratory tract was more severely injured than the lower.
Changes at 1,340 ppra included increased kidney weights in males and
slight hyperplastic and metaplastic changes of the tracheal
epithelium. No adverse effects were reported at 390 ppm. 5 "

Syrian golden hamsters exposed to acetaldehyde vapor at 1,500 ppm
for 7 h/d, 5 d/wk, for 52 wk developed epithelial hyperplasia and
metaplasia accompanied by nasal and tracheal inflammation. There was
no evidence of carcinogenicity produced by acetaldehyde. Some animals
were exposed to benzo[a]pyrene and diethylnitrosamine to study whether
acetaldehyde was a cof actor in respiratory tract carcinogenesis. This
part of the study produced insufficient evidence to determine any
cof actor effects . 3 la

Respiratory-System Effects

The adverse effect of cigarette smoke on the lungs has been
attributed in part to its acetaldehyde content (0.98-1.31
mg/cigarette) . 3a This was studied in mice by exposing them to
acetaldehyde at 1,390 ppm for 30 min twice a day, for 5 wk. A
reduction in functional residual capacity of the lung similar to that
seen in animals exposed to cigarette smoke was observed. 116 Other
studies involving ciliotoxic and cytotoxic effects of tobacco smoke
and its constituents have indicated that acetaldehyde is an important
compound in this regard. 38 ?t|

233
Cardiovascular-System Effect

Acetaldehyde, in common with other aliphatic aldehydes, has a
vasopressor effect i.e., it increases blood pressure. In inhalation
experiments, marked increases were seen in blood pressure at
concentrations of 1,665 ppm and higher. 23 When acetaldehyde was
administered by intraperitoneal injection, vasopressor effects were
produced at 5-20 mg/kg. At higher doses, a decrease in blood pressure
was a secondary response to a decrease in heart rate."

2 6

Metabolism

Acetaldehyde is a toxic intermediate in the metabolism of
ethanol. The main pathway involves an enzyme, alcohol dehydrogenase
(ADH) . Approximately 90% of the acetaldehyde formed from ethanol is
oxidized by the liver to acetic acid, which is converted to carbon
dioxide and water. The ADH-catalyzed oxidation of ethanol to
acetaldehyde has been extensively reviewed. 30 sa 59 63 108 lla

Carcinogenic Potential

The carcinogenic potential of acetaldehyde has not been defined by
appropriate long-term animal studies. Spindle-cell sarcomas were
produced in rats given repeated subcutaneous injections but metastasis
to other tissues was not reported. lls No marked pathologic changes
were reported in a group of rats fed a diet of ace taldehyde-con tain ing
rice for more than 300 d. Additional details are not available. 68

Mutagenic Potential

Acetaldehyde was not mutagenic in the standard Ames test with
Salmonella typhimurium. 19 It has some mutagenic activity in the
fruit fly Drosophila melanogaster , but this activity is much weaker
than that produced by formaldehyde. 78 The chromosome-breaking
potential of acetaldehyde has been indicated by the dose-dependent
sister chromatid exchanges in Chinese hamster ovary cells 69 and
human lymphocyte chromosomes . B 1

Embryotoxic and Teratogenic Potential

Acetaldehyde has shown embryotoxic and teratogenic effects in mice
similar to those produced by ethanol. Pregnant mice were given
intravenous injections of acetaldehyde at 40 or 80 mg/kg on days 7, 8,
and 9 of gestation. Acetaldehyde increased the percentage of embryos
resorbed and decreased their weight and their protein content.
Teratogenic effects included anomalies in closure of the cranial and
caudal regions of the neural tube. 73

234

HUMAN INVESTIGATIONS

Because of the explosive hazards of acetaldehyde, it is usually
handled in closed systems in industry and exposures are not apt to be
continuous or large. Therefore, occupational-exposure data are
lacking.

Acetaldehyde is readily detected well below 50 ppm. Some persons
can notice it below 25 ppm. At 50 ppm, a majority of volunteers
exposed for 15 min had some eye irritation; and at 200 ppm, all
subjects had redness of the eyes and transient conjunctivitis. 31

Eye irritation and, to a lesser extent, nose and throat irritation
are the only signs noted during exposure to the usual concentrations
encountered industrially. 31 The odor and eye-irritation thresholds
are 0.07 ppm* and 50 ppm, 6 respectively. The TC Lo (lowest toxic
concentration) for an observed health effect after inhalation is 134
ppm, and the threshold limit value is 200 ppm. 6 Acetaldehyde can
cause narcosis, bronchitis, albuminuria, fatty degeneration of the
liver, and pulmonary edema at high concentrations. Lethal doses cause
progressive slowing of heart and respiratory rates followed by
respiratory paralysis. There have been very few studies of persons
after industrial exposure. In one case, chronic exposure of workers
to acetaldehyde at 0.5-22 mg/m 3 (0.21-9.36 ppm) caused irritation of
the mucous membranes. 21

There have been many reports of the pharmacology of acetaldehyde
in relation to the effects of alcohol. Human subjects were given
intravenous infusions to increase blood concentrations to 0.2-0.7 mg%
(about 10 times normal). At these concentrations, heart rate and
respiratory ventilation were increased, and a "hangover" sensation is
noted. 31

Bittersohl 1 1 reported an increased prevalence of malignant
tumors in aldehyde workers. Of the 220 people employed in a plant,
150 had been employed for more than 20 yr. Nine neoplasms were noted
in males: two squamous-cell carcinomas of the oral cavity, one
adenocarcinoma of the stomach, one adenocarcinoma of the cecum, and
five squamous-cell carcinomas of the bronchial tree. The workers had
mixed exposures that included acetaldehyde, butyraldehyde,
crotonaldehyde , higher condensed aldehydes, butanol, hexatriol,
hexatetrol, octadiol, and butadiene. Of the nine employees, eight
smoked 5-10 cigarettes per day.

ACROLEIN

Acrolein is highly toxic by all routes of administration. Its
vapors cause severe respiratory and ocular irritation. Contact with
liquid acrolein can produce skin or eye necrosis. Serious injury is
produced even by a 1% aqueous solution. Acrolein has not been shown
to be carcinogenic or embryotoxic, but appears to be mutagenic in some
nonmammalian systems.

235

ACROLEIN IN ANIMALS
Acute Toxicology

By the oral route of administration, acrolein is highly toxic,
with reported LDgg values in rats, mice, and rabbits of 46
mg/kg, 100 40 mg/kg, 13 and 7.1 mg/kg (Shell Chemical Company,
unpublished data) , respectively. Acrolein is easily absorbed through
the skin of rabbits in lethal amounts (LD5Q, 168-562 mg/kg) (Shell
Chemical Company, unpublished data; Union Carbide Company, unpublished
data) . When applied undiluted, acrolein causes necrosis; even a 1%
aqueous solution can produce a burn on the abdominal skin of rabbits.

Likewise, instillation of a 1% solution into the rabbit eye caused
severe injury. 100

The marked toxicity of acrolein has also been shown by inhalation
exposures. In a 30-min exposure of rats, the LC^Q was 131 ppm; 97
in a 4-h exposure, it was 8 ppm. 100

Correspondingly low values have been reported for other species of
animals. Acrolein vapors are also very irritating to the eyes, nose,
and throat of laboratory animals, as well as man. Exposure of cats
and rats at approximately 12 ppm caused severe symptoms of eye and
respiratory tract irritation." * 66

Injection studies have demonstrated the high acute toxicity of
acrolein, with lethal doses of 30-50 mg/kg. 97

Extended Studies

Acrolein was added to the drinking water of rats, and that water
was administered as their only source of water for up to 90 d. The
unpalatability of the water was manifest in reduced body weights and
increased kidney weights. The death of animals given water containing
acrolein at 600-1,800 ppm was due to lack of water intake. No adverse
pathologic or hematologic changes were observed (G.W. Newell,
unpublished data; Union Carbide Company, unpublished data) .

Continuous inhalation of acrolein by rats for up to 90 d had
little or no effect at concentrations of 0.06-0.22 ppm. 12 ** 60
Dogs and monkeys appeared to be more sensitive to the vapors of
acrolein. in one of these studies, 60 no abnormal behavior was seen
at 0.22 ppm, but pathologic examination revealed acrolein-related
changes in the tracheas of the monkeys and lungs of the dogs. Higher
concentrations (1-1.8 ppm) produced visible signs of ocular and nasal
irritation throughout the 90-d period. In another study, 12 exposure
of rats at 0.55 ppm produced signs of irritation that subsided after
3-4 wk. The mean body weight of exposed animals was also
significantly lower than that of the controls. At 1-2 ppm, acrolein
induced minimal biochemical, pathologic, and functional injury of the
lower respiratory tract. The changes which included a decrease in
urinary vanillyl-mandelic acid and inflammatory infiltrates with mild
perivascular edema in the respiratory tract reached a peak during the
first month of exposure and then subsided. 39

236

During a continuous-inhalation study, groups of hamsters, rats,
and rabbits were exposed to acrolein at 0.4, 1.4, and 4.9 ppm for 6
h/d, 5 d/wk for 13 wk. Marked changes in the nasal epithelium were
evident in all species at the highest concentration. Histopathologic
examination revealed necrotizing rhinitis and squamous hyperplasia and
metaplasia of the epithelium. Rats appeared to be the most
susceptible species examined, with acrole in-related abnormalities
associated with 0.4 ppm exposure. This concentration was nontoxic to
both hamsters and rabbits. 3lf Lyon et^al^ 60 exposed rats, guinea
pigs, monkeys, and dogs to acrolein at 0.7 and 3.7 ppm for 8 h/d, 5
d/wk, for 6 wk or 24 h/d for 90 d at 0.21-1.8 ppm. No clinical signs
of toxicity were observed up to 0.7 ppm. Dogs and monkeys were
visibly affected by respiratory irritation at the greater exposures.
Repeated exposures at 0.7 ppm produced chronic inflammatory changes,
and 3.7 ppm caused squamous metaplasia of the lungs in monkeys.
Continuous exposure at 0.22 ppm resulted in moderate emphysema, acute
congestion of the lungs, and squamous metaplasia and oasal cell
hyperplasia of the trachea.

In a chronic study, 36 hamsters were exposed at 4.0 ppm, 7 h/d, 5
d/wk for 52 wk. The irritation produced by this concentration of
acrolein was initially manifest by salivation, nasal discharge,
restlessness, and the animals' keeping their eyes closed. The animals
apparently became acclimated to the vapors and behaved normally after
the second week of exposure, except for increased restlessness
(compared with the controls) . At the end of the exposure period, six
animals were sacrificed and the rest held for an additional 29-wk
recovery period. The animals exhibited rhinitis and hyperplastic and
metaplastic changes of the nasal epithelium. 33 No evidence of
carcinogenicity was seen.

Respiratory-System Effects

Groups of mice and guinea pigs were exposed to low concentrations
of acrolein. In mice, a concentration of 1.7 ppm produced a 50%
decrease in respiratory rate. 50 Another group was exposed to a
mixture of acrolein and formaldehyde. A 50% decrease in respiratory
rate was produced at a combination of 1.87-ppm acrolein and 1.42-ppm
formaldehyde; hence, the effect is not additive. 1 * 9 A group of
guinea pigs exposed to acrolein at 0.4-1.0 ppm for 2 h showed definite
decreases in respiratory rate. 67 in a study with dogs, it was shown
that acrolein is taken up more readily by the upper respiratory
system, but the uptake is considerably less than that of
formaldehyde . 2 *

Cardiovascular -System, Effects

Acrolein, in common with many other aldehydes, causes an increase
in blood pressure (vasopressor effect) . Anesthetized rats were given
acrolein at 0.05-5.0 mg/kg by intravenous injection or exposed at

237

4.4-2,200 ppm for 1 min. With intravenous doses up to 0.25 mg/kg, an
increase in blood pressure predominanted as an effect. At higher
doses, a decrease in blood pressure predominated. With exposure by
inhalation, a vasopressor effect of increasing magnitude was observed
within 15 s after the onset of exposure. Within 10 s after exposure
ceased, there was a rapid return to normal. 25

Metabolism/Pharmacokinetics

Acrolein is formed during thfe degradation of oxidized spermine and
spermidine. It is a probable metabolite of allyl alcohol and has been
shown to be a metabolite of the antitumor agent cyclophosphamide. 21

Carcinogenic Potential

Acrolein was not carcinogenic in a 52-wk inhalation study in
hamsters. 33 Preliminary results from an NCI-sponsored inhalation
study, also in hamsters, confirm this conclusion. 21 Acrolein did
not produce sarcomas in a subcutaneous-injection study in mice. 105
When tested by skin application in a promotion-initiation study with
croton oil, acrolein had little or no tumor-initiating activity. 82
Similarly, it had no effect on the carcinogenic activity of
diethylnitrosamine and had a minimal effect on the activity of
benzo[a]pyrene. 39

Mutaqenic Potential

Acrolein showed some mutagenic activity in the Ames test.
Mutagenic effects were observed in Salmonella typhimurium strains TA
1538 and TA 98 (strains that detect frameshift mutations) , whereas no
activity was seen in strains TA 1535 and TA 100 (strains that detect
base-pair substitutions) . 9 In another test of the Ames type,
acrolein did not induce point mutations in eight strains of
histidine-dependent mutants of S_. typhimurium. The authors indicated
that this test might not be able to identify weak mutagens. 7
Acrolein had mutagenic activity in the fruit fly Drosophila
melanogaster 7 8 and in a DNA-polymerase-def icient Escherichia
coli. 10 However, no activity was seen in strains of J. coli capable
of detecting forward and reverse mutations. 27 28 No activity was
seen in yeast Saccharomyces cerevisiae* 5 or in a dominant-lethal
assay in mice. 29

Embryotoxic and Teratogenic potentiaJL

Acrolein did not exhibit embryotoxicity in an inhalation study in
rats. Male and female rats were continuously exposed at 0.55 ppm and
allowed to mate after the fourth day of exposure. No significant

238

differences could be observed at this low concentration between
control and test animals in number of pregnant animals, number of
fetuses, or mean fetal weight. 12 The fetuses were not examined for
malformations; therefore, no information on teratogenic potential is
available from this study. No evidence of teratogenicity was observed
in embryos from acrolein-treated chicken eggs. 51

ACROLEIN IN HUMANS

Acrolein is predominantly an ocular and respiratory irritant. Its
toxicity can involve the senses, reflexes, nervous system, and
respiratory system, alter biochemical reactions, and affect the
composition of blood at 0.2-6.0 ppm. 17 Its conjugated unsaturated
bonds at the 1,2-position result in eye irritation (threshold, 0.2
ppm 17 ) 2.5 times greater than that from formaldehyde. 2 At higher
concentrations (0.5-1.0 ppm), this difference increases to 4-5
times. l Such irritancy is particularly important, because acrolein,
as a partially oxidized organic emission, is a major contributor to
the irritant quality of cigarette smoke 117 and photochemical
smog. 17 Acrolein in Los Angeles smog was thought to be responsible
for 35-75% as much eye irritation as formaldehyde (the major aldehyde
in auto exhaust). 2 The occupational threshold limit value for
acrolein (0.1 ppm) is low enough to minimize irritation in exposed
persons: 0.25 ppm is considered to be moderately irritating, 0.5 ppm
is thought to be a practical working concentration, and 1 ppm causes
marked irritation of the eyes and nose with lacrimation in less than 5
min.

The principal site of attack of acrolein is the mucous,, membranes
of the upper respiratory tract; high concentrations can produce
pulmonary edema. Table 8-8 lists human responses to various
concentrations of acrolein. The results of several studies concerning
eye irritation are found in Table 8-9.

Descriptions of acrolein toxicity are largely in the form of
ocular-irritation studies. However, the conclusions drawn from these
studies should be tempered, because the relationships between
atmospheric acrolein concentrations and indexes of eye irritation are
nonlinear and subject to a large element of variability. 72 79
Ocular exposure to 0.5% acrolein for 5 rain 95 caused discomfort with
stinging in 30-60 s and lacrimation, pain, and eyelid flickering and
heaviness in 3-4 min. Attesting to the variability of ocular
response, a chronaximetric study of the eyes of three persons showed
reduced chronaxy in two subjects at 0.64 ppm, but prolonged chronaxy
in the third. The optical-chronaxy reflex threshold was determined to
be about 0.7 ppm. Similarly, sensitivity to light was increased or
decreased and then gradually returned to normal. The optical-chronaxy
method of eye-irritation detection may not be sensitive enough,
inasmuch as other studies 17 H 3 e7 117 have indicated lower
eye-irritation thresholds measured by the more subjective methods of
blink response, lacriroation, or pain response.

239

TABLE 8-8
Thresholds of Response after Exposure to Acrolein

Acrolein
Concentration, ppm

0.2 a

0.33-0.40 a

0.40-l.U

0.62

0.73

0.8

1.0

5.5

_>10.0 (vapor, estimated)

24.0

Response

Eye-irritation threshold 1
Odor threshold 3 ' 6 ' 87
Prolonged deep respiration

87

Respiratory-response threshold

6

Chronaxime trie-response threshold
Severe mucosal irritation
Immediately detectable
Intense irritation
Lethal in a short time
Unbearable

6,77

a ln a simulated-smog study, the acrolein eye-irritation threshold (withou
olfaction) for a 30-s exposure was 1.27 ppm, and the odor threshold was
0.08-0.29 ppm. 1 The eye-irritation threshold was the same whether dete
mined by increasing concentrations over a constant period or by increasi
the duration of exposure over a series of concentrations (M. Jones,
H. Buchberg, K. Lindh, and K. Wilson, unpublished data).

240

TABLE 8-9
Ocular Response to Airborne Acrolein a

Ocular Exposure Duration of
Concentration, ppm Exposure Effect

0.8 10 min Extremely irritating; only just tolerable

1-2 5 min 87% of test panel reported irritation

1 5 rain 82% of test panel reported irritation

0.5 5 min 35% of test panel reported irritation

0.5 5 min 19% of test panel reported irritation

0.5 12 min 91% of test panel reported irritation

1.8 30 s (Odor)

1 min Slight irritation

2 min Distinct irritation (and slight nasal

irritation)
4 min Profuse lacrimation; practically

intolerable
5.5 5s Moderate irritation (and odor and

moderate nasal irritation)
20 s Painful irritation (and painful nasal

irritation)

60 s Marked lacrimation; practically intoleral
21.8 Intolerable

30.25 5 min Moderate irritation

4 5 min Severe irritation

0.06 Irritation 0.471 on scale of 0-2

1.3-1.6 Irritation 1.182 on scale of 0-2

2.0-2.3 Irritation 1.476 on scale of 0-2

a. 48

Reprinted with permission from Kane.

241

Inhalation of acrolein at 0.22-0.75 ppm 87 has generally resulted
in a depressed respiratory rate due to its anesthetic effect, 77 I17
although 1 ppm has been found to be tolerated with no significant
respiratory change. ^ Higher inhaled concentrations result in
respiratory irritation. The TC Lo for irritation of the upper
respiratory tract is 1 ppm, 11 although nasal irritation occurs at
lower concentrations. 21 " 3 e7

In liquid form, acrolein causes severe skin irritation. 5 Dermal
application of a 1% solution produced a positive patch test. 21

The effects of acrolein on biochemical functions have not been
thoroughly studied. 21 87 At 0.22 ppm or higher, prolonged
inhalation caused a reduction in lung lactic dehydrogenase. Acrolein
is highly reactive with thiol groups (this is related to its
lacrimatory effect) , and it can rapidly conjugate with glutathione and
cysteine. Acrolein is also a potent in vitro inhibitor of human
polymorphonuclear leukocyte chemotaxis (EC 5 Q, 15 urn) , but has no
effect on leukocyte integrity or glucose metabolism. Chemotaxis is
assumed to be inhibited by the reaction of acrolein with essential
thiol groups of cellular proteins involved in chemotaxis. A decrease
in cholinesterase activity and an alteration of liver enzyme activity
have also been noted. 87

Industrially, acrolein is expected to cause serious intoxication
only rarely, because of human intolerance of its irritating effects.
The inhalation LC^Q (lowest lethal concentration) for humans has
been estimated at 153 ppm for a 10-min exposure. 101 * Two cases of
occupational poisoning (one fatal) have been reported. 81 * It is
speculated that the greatest occupational danger of acrolein poisoning
is associated with the welding of fat and oil cauldrons.

The EPA has determined that, for protection of human health from
the toxic properties of acrolein ingested through water and
contaminated aquatic organisms and through contaminated aquatic
organisms alone, the ambient-water criteria are 0.320 and 0.780 mg/L,
respectively. 1I2

OTHER ALDEHYDES

Tables 8-2, 8-3, and 8-4 list toxicity information on other common
aldehydes. The eye and respiratory tract irritation caused by
formaldehyde, acrolein, and, to some extent, acetaldehyde is also
caused by propionaldehyde , 9 6 10 butyraldehyde (Sim and Pattle; 96
Smyth et^al^; 100 * * Du Pont Company, unpublished data), and chloral
(Du Pont Company, unpublished data) . Chloral is unique, in that its
inhalation toxicity puts it in the highly toxic category (Du Pont
Company, unpublished data). However, it is widely used as a sedative.
Chloral has also been shown to be mutagenic in the Ames test (Minnich
e_t_al_. ; 65 Du Pont Company, unpublished data) and has shown some
embryotoxic properties. 110 None of the other aldehydes have
toxicity values that would be inconsistent with the values typical of
their class.

242
BENZALDEHYDE

No information is available on the human health effects of
benzaldehyde . Increased concentrations were found in the blood of New
Orleans residents during 1970-1975. 57

BUTYRALDEHYDE AND ISOBUTYRALDEHYDE

These aldehydes are not human irritants. The estimated inhalation
TC Lo of butyr aldehyde 101 * is 580 mg/m 3 . Exposure at 200 ppm for
30 min results in no irritant effects. 5 However, isobutyr aldehyde
at the same concentration causes nausea. 6 Butyraldehyde has been
implicated 11 as an etiologic factor in the cancer epidemiologic
study discussed in the section on acetaldehyde.

CHLORAL HYDRATE

Chloral hydrate is converted to trichloroethanol and
trichloroacetic acid in man. Some of the alcohol derivative is
excreted as the glucuronide. Bromal hydrate is metabolized
differently and is more toxic. 31

CHLOROACETALDEHYDE

Chloroacetaldehyde is somewhat more irritating to the eye, nose,
and throat than is formaldehyde. Contact with a 40% aqueous solution
produces serious eye injury and skin corrosion. 1 * Dilute aqueous
solutions of 0.1% are capable of causing marked skin irritation. The
carcinogenic activity of vinyl chloride has been attributed to its
metabolic activation in the liver to 2-chloroacetaldehyde.
2-Chloroacetaldehyde increases the revertant power of 3. typhimurium
mutant strains; this suggests that the presence of an oxidase in the
microsomal fraction of human liver is responsible for converting vinyl
chloride to mutagenic metabolites. 8

CROTONALDEHYDE (R -METHYL ACROLEIN)

Crotonaldehyde , whose threshold limit value of 2 ppm is based on
animal studies, 1 * produces symptoms similar to those produced by
acrolein. A strong odor is detectable at 15 ppm, and exposure at 45
ppm results in disagreeable, conjunctival irritation. An increased
cancer incidence in workers exposed to crotonaldehyde and other agents
is discussed in the section on acetaldehyde. 11

243

FURFURAL

There are conflicting reports on the toxicity of furfural. One
report indicating only mild effects contrasts with another describing
numbness of the buccal membranes and tongue, loss of taste, and
respiratory distress. 81 * The latter report indicated that 1.9-14 ppm
caused bloodshot eyes, lacrimation, throat irritation, headache, and
possibly damage to eyesight. Furfural is metabolized by conversion of
the aldehyde group to an acid and conjugation with glycine. 31 Other
than an occasional allergic skin manifestation, no injury from
occupational exposure to furfural has been reported. 31 The
inhalation TCLo has been estimated 101 * at 600 yg/m 3 . As a
result of the primary irritation induced by furfural, a threshold
limit value of 5 ppm has been established.

Feron 32 conducted an intratracheal-instillation study in Syrian
golden hamsters with furfural, benzo[a]pyrene, and benzo[a]pyrene plus
furfural. Furfural alone produced no evidence of carcinogenic
activity, but the results suggested a cocarcinogenic effect of
furfural on the respiratory tract of hamsters. In comparison with
treatment with benzo[a]pyrene alone, intratracheal instillation of
benzo[a]pyrene plus furfural resulted in earlier development of
metaplastic changes of the tracheobronchial epithelium, a shorter
latent period for tracheobronchial tumors, and a few more bronchial
and peripheral squamous-cell carcinomas.

GLUTARALDEHYDE

Glutaraldehyde is a strong nasal irritant and a mild optic or
dermal irritant. Occasional dermal contact can cause an allergic
response leading to contact dermatitis. Activated glutaraldehyde (pH,
7.5-8.0) is a stronger irritant and affects the upper respiratory
tract. Occupationally, a 2% aqueous solution (0.38 ppm) in an
operator's breathing zone produces severe eye, nose, and throat
irritation and headache. This has led to the establishment of a
threshold limit value (ceiling) of 0.2 ppm. "

Glutaraldehyde at 5-10% has been effective in reducing
hyperhidrosis. 20 36 37 l * 7 86 Sensitization to glutaraldehyde occurs
much less frequently than sensitization to formaldehyde, and
cross-reaction of formaldehyde-sensitive subjects does not seem to
occur. i Strong staining of the skin limits the usefulness of
glutaraldehyde. As with formaldehyde, the blockage of sweating can be
reversed by stripping the stratum corneum with tape. 36 75 e6

GLYOXAL

The antitumor activity of glyoxal has been mentioned. 87
Concentrations of 0.5 mM or higher inhibit human fibroblast cell
division and synthesis of DNA, RNA, and proteins. 8

244
4 -HYDROXYPENTENAL

This compound inhibits mitosis in human kidney cells and is 4
times as active an inhibitor as kethoxal. 87

KETOALDEHYDES

Ketoaldehydes complexed with hydrogen sulfite and an ammo group
were less harmful than free aldehydes in tumor therapy. These
complexes showed significant antitumor activity in in vitro
adenocarcinomas cultured from breast and colon tissues and in
epidermal carcinoma. 87

MALONALDEHYDE

Reaction of malonaldehyde (50 yg/ml) with DNA from human
fibroblasts reduces hypochroraia, changes the "temperature-absorption
curve," and increases resistance to degradation by DNase. 87
Malonaldehyde is a product of peroxidative fat metabolism and is
formed in the tissues of animals whose diet is deficient in
antioxidants. Shamberger ejt ail. 9 3 applied malonaldehyde once to the
shaved backs of female Swiss mice. Daily treatment with 0.1% croton
oil produced tumors in 52% of the mice at 30 wk. Malonaldehyde
concentrations in mouse skin increased after application of
benzo[a]pyrene, 7, 12-dimethylbenz [a] anthracene, and
3-methylcholanthrene. A weak link has also been established from
epidemiologic data between beef fat in the diet, malonaldehyde content
in beef, and the incidence of large bowel cancer. 91 See the
discussion in Schauenstein _et jal. 8 7 (Chapter 5) for additional
discussion of the metabolism of malonaldehyde.

PROPIONALDEHYDE AND AMINOPROPIONALDEHYDE

Inhalation of propionaldehyde at 134 ppm for 30 mm, or 0.1-6.0
ug/m f has been demonstrated to cause mild irritation of mucosal
surfaces. 6 21 8 -Aminopropionaldehyde is a natural component of
human serum. A decrease in its oxidation leads to its accumulation,
with an additional accumulation of spermidine and a decrease in
malonaldehyde. Increases in propionaldehyde and spermidine cause an
increase in RNA synthesis. 87 Propionaldehyde is a skin carcinogen
whose structure resembles that of malondialdehyde. 9 2

SYNAPALDEHYDE (CINNAMALDEHYDE)

Cinnamaldehyde is a natural ingredient in the essential oils of
cinaramon leaves and bark, hyacinth, and myrrh. It is used primarily
as a fragrance in soaps, creams, lotions, and perfumes.

245

Cinnamaldehyde is oxidized to cinnamic acid, which is further degraded
to benzoic acid; 118 much of it shows up in the urine of rats as
hippuric acid. x 9

When administered by intubation to rats and guinea pigs, cinnamic
aldehyde had an LD 50 of 2,220 and 1,160 mg/kg, respectively. The
toxicity in rats was expressed as depression, diarrhea, and a scrawny
appearance. * 6 The intraperitoneal LD 50 of Cinnamaldehyde in mice
was 2,318 rag/kg, and its oral LD 50 in rats was 3,350 mg/kg.

In a study of the toxicity of synthetic and natural products, the
LD 100 s in mice were 6,000 and 12,000 mg/kg, respectively. In
chronic-toxicity studies, liver lipid content was reportedly increased
by 20% in the first generation and 22% in the second generation. 103

Published reports indicate that Cinnamaldehyde is a skin irritant
and strong sensitizer. Sensitization reactions have been produced in
guinea pigs after challenge with 0.5% Cinnamaldehyde by the method of
Buehler. 107 Kligman 52 53 tested Cinnamaldehyde on human subjects
at 3% and 8% in petrolatum. The lower concentration produced no
irritation, but the 8% concentration was severely irritating. Studies
completed by the North American Contact Dermatitis Research Group
indicated that Cinnamaldehyde may be a frequent cause of allergic
reactions to perfumes. 89 This Group and Schorr 90 reported
positive reactions to Cinnamaldehyde in more than 3% of those tested.

When tested in rabbits, Cinnamaldehyde converted resting EEC
patterns to arousal patterns in the gallamine-paralyzed preparation
with the intact brain. A centrally originating deactivation was
produced through direct and indirect excitatory action on the
brainstem reticular formation. 1 * 1 It also produced positive
inotropic and chronotropic effects in isolated guinea pig heart
preparations and hypotensive effects in anesthetized dogs and guinea
pigs secondary to its peripheral vasodilatation. l * 2

Cinnamaldehyde was shown to be weakly mutagenic, with a tendency
to produce nondis junction in tests using late embryos and young larvae
of Drosophila melanogaster . : x ** The incidence of primary lung tumors
in both male and female A-strain mice was not increased over control
values after intraperitoneal injection at 4.00 or 0.8 g/kg over an
8-wk period. 106

Epidemiologic evidence from a study in Buckinghamshire in
Oxfordshire, England, suggested increased nasal and sinus cancers in
woodworkers of the furniture industry. l Other investigators have
not found a relationship between occupation and nasopharyngeal cancer
in retrospective surveys. 18 56 62 9 * Nasopharyngeal cancers are
apparently found in a wide variety of occupations, and Buell, 16
using occupation as an indicator of economic status, found a twofold
excess of nasopharyngeal cancers among those of lower socioeconomic
status.

As a result of these epidemiologic findings, a number of
constituents of wood are being tested for carcinogenic activity,
including the lignin constituents, methoxy-substituted
cinnamaldehydes, and cinnamalcohols. The latter would yield respective
aldehydes in the course of metabolic oxidation by alcohol
dehydrogenases. Preliminary data indicate that 3,4,5-

246

trimethoxycinnamaldehyde is a potent carcinogen and may be involved in
the carcinogenic action of some woods and their products. 88
Cinnaraaldehyde has not been shown to be carcinogenic, but
glycidaldehyde (2,3-epoxypropionaldehyde) has been shown to be
carcinogenic in mice and rats. 113

HeLa cells in permanent culture suffered irreversible damage from
exposure to 50 mM glycer aldehyde, with high toxicity at concentrations
lower by a factor of 10-100. 87 The HeLa cells produced
4-hydroxy-2-oxobutanal as a bacteria-inhibiting factor. 87

VALERALDEHYDE AND I SOVALERALDEHYDE (2-METHYLBUTYRALDEHYDE)

Human data on valeraldehyde are not available. A threshold limit
value of 50 ppm is based on animal data. 1 * Several chemists engaged
in distilling i sovaler aldehyde 3 l developed chest discomfort, nausea,
emesis, and headaches. Although exposures were not measured, the odor
was pronounced, and ambient concentrations may have been high. All
symptoms were reversed within a few days without further consequence.

MISCELLANEOUS

Eye Irritation from Oxidation Products of Paraffinic, Olefinic, and
Aromatic Hydrocarbons and Aldehydes

Photochemical auto smog consists largely (ca. 15%) of unburned and
partially oxidized organic materials, including aliphatic, olefinic,
and aromatic hydrocarbons, and aldehydes. Gaseous NO-^ is also
present as an oxidant. 17

Chemical reactivity increases in the order of paraffinic
hydrocarbons < ethylene, toluene, propionaldehyde < 1-butene,
1,3-butene, 1,3,5-trimethylbenzene. 3 In measurements of human eye
irritation caused by oxidation products of these compounds combined
with NOx, 1,3-butadiene proved to be the most potent (eye irritation
index, 20 on a 1-30 scale). Less-saturated or shorter-chain olefins
produced less eye irritation, and isolated oxidized olefins at
concentrations of less than 1 ppm produced no irritation. Of the
aromatic hydrocarbons, 45% oxidation of mesitylene to aliphatic
aldehydes produced only slight eye irritation (index, 6 on a 1-30
scale). In contrast with the strong irritating effect of oxidized
olefinic hydrocarbon mixtures, olefinic and aromatic hydrocarbons
together, when oxidized, produced only slight irritation. Oxidation
of 3.5-ppm propionaldehyde produced 0.08-ppm formaldehyde, which
resulted in moderate eye irritation (index, 8 on a 1-30 scale) . Lower
propionaldehyde concentrations resulted in only slight irritation. 3
In combination with acetaldehyde , oxidation resulted in eye irritation
of 0.2-2.1 on a scale with an upper limit of 5. 2 For constituents
of photochemical smog, variations in eye-irritation threshold appear
to be due to the amount of unsaturated hydrocarbon present in the
smog. The thresholds of saturated hydrocarbons oxidized to saturated

247

aldehydes are lower than expected. This suggests the presence of
unsaturated aldehyde (e.g., acrolein) resulting from the oxidation of
unsaturated precursors. 15

^Naturally Occur rinq Aldehydes

In addition to the presence of propionaldehyde as a natural
constituent of human blood, several other aldehydes are also natural
body constituents. Some of these higher, naturally occurring
aldehydes and their functions are as follows: 87

Indol-3-ylacetaldehyde J Metabolic products of tryptophan
5-Hydroxyindol-3-ylacetaldehyde /

Pyridoxal phosphate and pyridoxal Coenzymes and catalysts
Retinal and dehydroretinal Vitamins A! and A 2 /

respectively; parts of the

light-sensitive optic pigments

(rhodopsin)
Collagenaldehyde Part of the collagen

cross-linkage reaction mechanism

These and other aldehydes (formaldehyde, acetaldehyde,
butyr aldehyde, isobutyraldehyde, and crotonaldehyde) are oxidized to
the acid form by formyl hydrate dehydrogenase , which is in human blood
serum. 87

REFERENCES

Acheson, E. D. , R. H. Cowdell, E. Hadfield, and R. G. Macbeth.

Nasal cancer in woodworkers in the furniture industry. Br. Med.

J. 2:587-596, 1968.

Altshuller, A. P. Assessment of the contribution of chemical

species to the eye irritation potential of photochemical smog.

J. Air Pollut. Control Assoc. 28:594-598, 1978.

Altshuller, A. P., D. L. Klosterman, P. W. Leach, I. J. Hindawi,

and J. E. Sigsby, Jr. products and biological effects from

irradiation of nitrogen oxides with hydrocarbons or aldehydes

under dynamic conditions. Int. J. Air Wat. pollut. 10:81-98,

1966.

American Conference of Governmental industrial Hygienists inc.

Documentation of the Threshold Limit Values. Fourth Edition.

1980. Cincinnati: American Conference of Governmental

Industrial Hygienists Inc., 1980. 486 pp.

American Industrial Hygiene Association. Acrolein. Hygiene

Guide Series. Detroit: American Industrial Hygiene

Association, 1963. 3 pp.

American Industrial Hygiene Association. Community air quality

guides. Aldehydes. J. Am. Ind. Hyg. Assoc. 29:505-512, 1968.

248

7. Andersen, K. J., E. G. Leighty, and M. T. Takahashi. Evaluation
of herbicides for possible mutagenic properties. J. Agr. Food
Chem. 20:649-656, 1972.

8. Auerbach, C., M. Moutschen-Dahmen , and J. Moutschen. Genetic
and cytogenetical effects of formaldehyde and related
compounds. Mutat. Res. 39:317-362, 1977.

9. Bignami, M. , G. Cardamone, P. Comba, V. A. Ortali, G. Morpurgo,
and A. Car ere. Relationship between chemical structure and
mutagenic activity in some pesticides. The use of Salmonella
typhimurium and Aspergillus nidulans. Mutat. Res. 46:243-244,
1977.

10. Bilimoria, M. H. The detection of mutagenic activity of
chemicals and tobacco smoke in a bacterial system. Mutat. Res.
31:328, 1975.

11. Bittersohl, G. Epidemiological research on cancer risk by aldol
and aliphatic aldehydes. Environ. Qual. Saf. 4:235-238, 1975.

12. Bouley, G. , A. Dubreuil, J. Godin, M. Biosset, and C. Boudene.
Phenomena of adaptation in rats continuously exposed to low
concentrations of acrolein. Ann. Occup. Hyg. 19:27-32, 1976.

13. Boyland, E. Experiments on the chemotherapy of cancer. 4.
Further experiments with aldehydes and their derivatives.
Biochem. J. 34:1196-1201, 1940.

14. Boytsov, A. N., Y. S. Rotenberg, V. G. Mulenkova. lexicological
evaluation of chloral in the process of its liberation during
spraying and pouring of polyurethane foams. Gig. Tr. Prof.
Zabol. 14:26-29, 1970.

15. Buchberg, H. , M. H. Jones, K. G. Lindh, and K. W. Wilson, air
pollution studies with simulated atmospheres. Report No.
61-44. Los Angeles: University of California Department of
Engineering, 1961. 168 pp.

16. Buell, P. Nasopharynx cancer in Chinese of California. Br. J.
Cancer 19:459-470, 1965.

17. Campbell, K. I. Effects of gaseous air pollution on body
systems. Vet. Toxicol. 16:73-81, 1974.

18. Ch'in, K. Y., and C. Szutu. Lyraphoepithelioma. pathological
study of 97 cases. Chin. Med. J. 3 (Suppl.) : 94-119, 1940.

19. Commoner, B. Reliability of Bacterial Mutagenesis Techniques to
Distinguish Carcinogenic and Noncarcinogenic Chemicals. U.S.
Environmental Protection Agency Report No. 600/1-76/022. PB-259
934. Springfield, Va. : National Technical Information Service,
1976. 114 pp.

20. Cullen, S. I. Management of hyper hidros is. Postgrad. Med.
52:77-79, 1972.

21. Dirken, P. Acrolein. Ambient Water Quality Criteria.
Syracuse: Syracuse Research Corp., for U.S. Environmental
Protection Agency, 15 May 1979. (2nd draft)

22. Dixon, M. Reaction of lachrymators with enzymes and proteins,
pp. 39-49. In Biochemical Society Symposia No. 2. Cambridge,
England: Cambridge University Press, 1948.

249

23. Egle, J. L. , Jr. Effects of inhaled acetaldehyde and
propionaldehyde on blood pressure and heart rate. Toxicol.
Appl. Pharmacol. 23:131-135, 1972.

24. Egle, J. L., Jr. Retention of inhaled formaldehyde,
propionaldehyde, and acrolein in the dog. Arch. Environ. Health
25:119-124, 1972.

25. Egle, J. L., Jr., and p. M. Hudgins. Dose-dependent
sympathomimetic and cardioinhibitory effects of acrolein and
formaldehyde in the anesthetized rat. Toxicol. Appl. Pharmacol.
28:358-366, 1974.

26. Egle, J. L., Jr., p. M. Hudgins, and F. M. Lai. Cardiovascular
effects of intravenous acetaldehyde and propionaldehyde in the

anesthetized rat. Toxicol. Appl. Pharmacol. 24:636-644, 1973.

27. Ellenberger, J., and G. R. Mohn. Comparative mutagenicity
testing of cyclophosphamide and some of its metabolites. Mutat.
Res. 38:120-121, 1976.

28. Ellenberger, J., and G. R. Mohn. Mutagenic activity of major
mammalian metabolites of cyclophosphamide toward several genes
of Escherichia coll. J. Toxicol. Environ. Health 3:637-650,
1977.

29. Epstein, S. S., E. Arnold, J. Andrea, W. Bass, and Y. Bishop.
Detection of chemical mutagens by the dominant lethal assay in
the mouse. Toxicol. Appl. Pharmacol. 23:288-325, 1972.

30. Eriksson, C. J. P., and H. W. Sippel. The distribution and
metabolism of acetaldehyde in rats during ethanol oxidation I.
The distribution of acetaldehyde in liver, brain, blood and
breath. Biochem. Pharmacol. 26:241-247, 1977.

31. Fassett, D. W. Aldehydes and acetals, pp. 1959-1989. In D. W.
Fassett and D. D. Irish, Eds. Toxicology. Vol. 2. In F. A.
Patty, Ed. Industrial Hygiene and Toxicology. 2nd ed. New York:
John Wiley & Sons, Inc., 1963.

31a. Feron, V. J. Effects of exposure to acetaldehyde in Syrian
hamsters simultaneously treated with benzo(a)pyrene or
diethylnitrosamine. Prog. Exp. Tumor Res. 24:162-176, 1979.

32. Feron, V. J. Respiratory tract tumors in hamsters after
intratracheal instillations of benzo[a]pyrene alone and with
furfural. Cancer Res. 32:28-36, 1972.

33. Feron, V. J. , and A. Kruysse. Effects of exposure to acrolein
vapor in hamsters simultaneously treated with benzo [a] pyrene or
diethylnitrosamine. J. Toxicol. Environ. Health 3:379-394, 1977,

34. Feron, V. J., A. Kruysse, H. P. Til, and H. R. Immel. Repeated
exposure to acrolein vapour: Subacute studies in hamsters, rats
and rabbits. Toxicology 9:47-57, 1978.

35. Gage, J. C. Subacute inhalation toxicity of 109 industrial
chemicals. Brit. J. Ind. Med. 27:1-18, 1970.

36. Gordon, B. I., and H. I Maibach. Eccrine anhidrosis due to
glutar aldehyde, formaldehyde and iontophoresis. J. invest.
Dermatol. 53:436-439, 1969.

37. Gordon, H. H. Hyperhidrosis: Treatment with glutaraldehyde.

Cutis 9:375-378, 1972.

250

38. Guillerm, R. , R. Badre, and B. Vignon. Inhibitory effects of
tobacco smoke on the ciliary activity of the respiratory
epithelium and nature of the responsible constituents. Bull.
Acad. Nat. Med. Paris 145:416-423, 13-20 Jun 1961. (in French)

39. Gillerm, R. , J. Hee, M. Bourdin, H. Burnet, and G. Siou.
Contribution a la determination de la valeur 1 unite de
concentration de 1'acroleine. Cah. Notes Document. 77:527-535,
1974.

40. Gusev, M. I., A. I. Svechnikova, I. S. Dronov, M. D.
Grebenskova, and A. I. Golovina. Determination of the daily
average maximum permissible concentration of acrolein in the
atmosphere. Gig. Sanit. 31:8-13, 1966. (in Russian)

41. Harada, M. , Y. Fujii, and J. Kamiya. pharmacological studies on
Chinese cinnamon. III. Electroencephalographic studies of
cinnamaldehyde in the rabbit. Chem. Pharm. Bull. (Tokyo)
24:1784-1788, 1976.

42. Harada, M. , and S. Yano. Pharmacological studies on Chinese
cinnamon. II. Effects of cinnamaldehyde on the cardiovascular
and digestive systems. Chem. Pharm. Bull. (Tokyo) 23:941, 1975.

43. Hine, C. H. , F. Meyers, F. Ivanhoe, S. Walker, and G. H.
Takahashi. Simple tests of respiratory function and study of
sensory response in human subjects exposed to respiratory tract
irritants, pp. 28-30. In Proceedings of the Afternoon Sessions
of The First Day of the Air Pollution Medical Research
Conference, 4 December 1961, Los Angeles. Berkeley: California
State Department of Health, 1961.

44. Iwanoff, N. Experimentelle Studien uber den Einfluss technisch
und hygienisch wichtiger Gase und Dampfe auf den Organismus.
Teil XVI, XVII, XVIII. tiber einige praktisch wichtige Aldehyde
(Forraaldehyd, Acetaldehyd, Akrolein) . Arch. Hyg. 73:307-340,
1911.

45. Izard, C. Mutagenic effects of acrolein and its two epoxides:
glycidol and glycidal, in Saccharomyces cerevisiae. C. R. Acad.
Sci., Ser. D. 276:3037-3040, 1973. (in French)

46. Jenner, P. M. , E. C. Hagan, J. M Taylor, E. L. Cook, and G.
Fitzhugh. Food flavourings and compounds of related structure.
I. Acute oral toxicity. Food Cosmet. Toxicol. 2:237, 1964.

47. Juhlin, L., and H. Hansson. Topical glutaraldehyde for plantar
hyperhidrosis. Arch. Dermatol. 97:327-330, 1968.

48. Kane, L. E. Sensory Irritation from Photochemical Oxidant
Mixtures and Their Components: Development of an Animal Model
System. Dissertation. Pittsburgh: University of Pittsburgh,
Graduate School of Public Health, 1977. 124 pp.

49. Kane, L. E., and Y. Alarie. Evaluation of sensory irritation
from acrolein-formaldehyde mixtures. Am. Ind. Hyg, Assoc. J.
39:270-274, 1978.

50. Kane, L. E. and Y. Alarie. Sensory irritation to formaldehyde
and acrolein during single and repeated exposures in mice. Am.
Ind. Hyg. Assoc. J. 38:509-522, 1977.

251

51. Kankaanpa'a, j., E. Elovaara, K. Hemminki, and H. Vainio.
Embryotoxicity of acrolein, acrylonitrile and acrylamide in
developing chick embryos. Toxicol. Lett. 4: 93-96 f 1979.

52. Kligman, A. M. Report to Research Institute for Fragrance
Materials, 10 October 1973.

53. Kligman, A. M. Report to Research Institute for Fragrance
Materials, 22 August 1974.

54. Kruysse, A., V. J. Feron, and H. P. Til. Repeated exposure to
acetaldehyde vapor. Studies in Syrian golden hamsters. Arch.
Environ. Health 30:449-452, 1975.

55. Kryatov. I. A. Hygienic evaluation of sodium
p-chlorobenzenesulfonate and chloral as water pollutant. Hyg.
Sanit. 35:333-338, 1970.

56. La ing, D. Nasopharyngeal carcinoma in the Chinese in Hong
Kong. Trans. Amer. Acad. Ophthalmol. Otolaryngol. 71:934-950,
1967.

57. Laseter, J., and B. J. Dowty. Association of biorefractories in
drinking water and body burden in people, pp. 547-556. In H. F.
Draybill, C. J. Daive, J. C. Harshbarger, and R. G. Tardiff.
Aquatic Pollutants and Biological Effects with Emphasis on
Neoplasia. Ann. N. Y. Acad. Sci. 298, 1977.

58. Lieber, C. S. Metabolism of ethanol, pp. 1-29. In C. S.
Lieber, Ed. Metabolic Aspects of Alcohol. Baltimore:
University Park Press, 1977.

59. Lindros, K. 0. Acetaldehyde its metabolism and role in the
actions of alcohol. Res. Adv. Alcohol Drug Prob. 4:111-176,
1978.

60. Lyon, J. p., L. J. Jenkins, Jr., R. A. Jones, R. A. Coon, and J.
Siegel. Repeated and continuous exposure of laboratory animals
to acrolein. Toxicol. Appl. Pharmacol. 17:726-732, 1970.

61. Manufacturing Chemists' Association, Inc. Properties and
Essential Information for Safe Handling and use of
Acetaldehyde. Chemical Safety Data Sheet SD-43. Washington,
D.C.: Manufacturing Chemists' Association, inc., adopted 1952.

62. Martin, H. , and S. Quan. Racial incidence (Chinese) of
nasopharyngeal cancer. Ann. Otol. Rhinol. Laryngol. 60:168-174,
1951.

63. Matsuzaki, S., and C. S. Lieber. Metabolism and toxicity of
acetaldehyde in the liver. Saishin Igaku 31:2099-2107, 1976.

64. McLaughlin, R. S. Chemical burns of the human cornea. Am. J.
Ophthalmol. 29:1355-1362, 1946.

65. Minnich, V., M. E. Smith, D. Thompson, and S. Kornfeld.
Detection of mutagenic activity in human urine using mutant
strains of Salmonella typhimurium. Cancer 38:1253-1258, 1976.

66. Murphy, S. D. , H. V. Davis, and V. L. Zaratzian. Biochemical
effects in rats from irritating air contaminants. Toxicol.
Appl. Pharmacol. 6:520-528, 1964.

67. Murphy, S. D., D. A. Klingshirn, and C. E. Ulrich. Respiratory
response of guinea pigs during acrolein inhalation and its
modification by drugs. J. Pharmacol. Exp. Therap. 141:79-83,
1963.

252

68. Nakahara, W. , and K. Mori. Experimental production of liver
cirrhosis by furfural feeding. GANN 35:208-231, 1941.

69. Obe, G. , and B. Seek. Mutagenic activity of aldehydes. Drug
Alcohol Depend. 4 (1-2) :91-94, 1979.

70. Omel ' yanets , N. I., N. V. Mironets, N. V. Martyshchenko, I. A.
Gubareva, L. F. Piven, and S. N. Starchenko. Experimental
substantiation of the maximum permissible concentrations of
acetone and acetaldehyde in reclaimed potable water. Biol.
Aviakosra. Med. 1978:67-70, 1978. (in Russian)

71. Opdyke, D. L. J. Inhibition of sensitization reactions induced
by certain aldehydes. Pood Cosmet. Toxicol. 14:197-198, 1976.

72. Orcutt, J. A., and J. R. Taylor. Correlation of Eye Irritation
with Concentrations of Ambient Air Contaminants by probit
Analysis of the Quantal Response of Human Panels, preliminary
Results of APCD-APF Project 60. Analysis Paper No. 36. Los
Angeles: County of Los Angeles Air pollution Control District,
28 November 1960.

73. O'Shea, K. S., and M. H. Kaufman. The teratogenic effect of
acetaldehyde: implications for the study of the fetal alcohol
syndrome. J. Anat. 128:65-76, 1979.

74. Pace, D. M. , and A. Elliott. Studies on the effects of
acetaldehyde on tissue cells cultivated ^ri vitro. Cancer Res.
20:868-875, 1966.

75. Papa, C. M. , and A. M. Kligman. Mechanism of eccrine
anhidrosis. I. High level blockage. J. Invest. Derma tol.
47:1-9, 1966.

76. Pavlova, L. P. lexicological characteristics of
trichloroacetaldehyde. Tr. Azerb. Nauchno-lssled. Inst. Gig.
Tr. Prof. Zabol. 1975:99-105, 1975. (in Russian)

77. Plotnikova, M. M. Acrolein as an atmospheric air pollutant.
Gig. Sanit. 22:10-15, 1957. (in Russian)

78. Rapoport, I. A. Mutations under the effect of unsaturated
aldehydes. Dokl. Akad. Nauk S.S.S.R. 61:713-715, 1948. (in
Russian)

79. Renzetti, N. A., and R. J. Bryan. Atmospheric sampling for
aldehydes and eye irritation in Los Angeles smog 1960. J. Air
Pollut. Control Assoc. 11:421-424, 427, 1961.

80. Riley, J. F. , and A. B. Wallace. Stimulation and inhibition of
connective tissue in mice following injection of benzpyrene.
Br. J. Exper. Pathol. 22:24-28, 1941.

81. Ristow, H., and G. Obe. Acetaldehyde induces cross-links in DNA
and causes sister-chromatid exchanges in human cells. Mutat.
Res. 58:115-119, 1978.

82. Salaman, M. H., and F. J. C. Roe. Further test for
tumour-initiating activity: N,N-di-(2-chloroethyl)--
aminophenylbutyric acid (CB1348) as an initiator of skin tumour
formation in the mouse. Br. J. Cancer 10:363-378, 1956.

83. Salem, H. , and H. Cullumbine. Inhalation toxicities of some
aldehydes. Toxicol. Appl. Pharmacol. 2:183-187, 1960.

84. Santodonato, J., J. E. Hoecker, D. Orzel, and w. Meylan.
Information profiles on Potential Occupational Hazards Classes

253

of Chemicals. Syracuse, New York: Syracuse Research
Corporation, Center for Chemical Hazard Assessment, for the
National Institute for Occupational Safety and Health, 1978.
14 pp.

85. Sasaki, Y., and R. Endo. Mutagenicity of aldehydes in
Salmonella. Mutat. Res. 54:251-252, 1978.

86. Sato, K., and R. L. Dobson. Mechanism of the antiperspirant
effect of topical glutaraldehyde. Arch. Dermatol. 100:564-569,
1969.

87. Schauenstein, E., H. Esterbauer, and H. Zollner. Aldehydes in
Biological Systems. Their Natural Occurrence and Biological
Activities. London: Pion Limited, 1977. 205 pp.

88. Schoental, R. Chapter 12. Carcinogens in plants and
microorganisms, pp. 626-689. In Searle, C. E., Ed. ACS
Monograph No. 173: Chemical Carcinogens. Washington, D.C. :
American Chemical Society, 1976.

89. Schorr, W. F. Allergic skin disease caused by cosmetics. Am.
Fam. Physician 12:90-95, September 1975.

90. Schorr, W. F. Cinnamic aldehyde allergy. Contact Dermatitis
1:108, 1975.

91. Shamberger, R. J. Antioxidants and cancer. VII. Presence of
malonaldehyde in beef and other meats and its epidemiological
significance, pp. 36-43. In D. D. Hemphill, Ed. Trace
Substances in Environmental Health. XI. Proceedings of
University of Missouri's llth Annual Conference on Trace
Substances in Environmental Health, June 7-9, 1977, Columbia,
Missouri. Columbia, Mo.: Curators of the University of
Missouri, 1977.

92. Shamberger, R. J. Increase of peroxidation in carcinogenesis.
J. Nat. Cancer Inst. 48:1491-1497, 1972.

93. Shamberger, R. J., T. L. Andreone, and C. E. Willis.
Antioxidants and cancer. IV. Initiating activity of
malonaldehyde as a carcinogen. J. Nat. Cancer Inst.
53:1771-1773, 1974.

94. Shanmugaratnam, K., and J. Higginson. Pp. 130-134. In C. S.
Muir and K. Shanmugaratnam, Eds. Cancer of the Nasopharynx.
Copenhagen: Munksgaard, 1967.

95. Shimizu, K. , M. Harada, M. Miuata, S. Ishikawa, and I.
Mizoguchi. Effect of photochemical smog on the human eye. J.
Clin. Ophthalmol. 30:407-418, 1976.

96. Sim, V. M. , and R. E. Pattle. Effect of possible smog irritants
on human subjects. J. Am. Med. Assoc. 165:1908-1913, 1957.

97. Skog, E. A toxicological investigation of lower aliphatic
aldehydes. I. Toxicity of formaldehyde, acetaldehyde ,
propionaldehyde and butyraldehyde; as well as of acrolein and
crotonaldehyde . Acta Pharmacol. 6:299-318, 1950.

98. Smyth, H.F., Jr., and C. P. Carpenter. The place of the range
finding test in the industrial toxicology laboratory. J. Ind.
Hyg. Toxicol. 26:269-273, 1944.

254

99. Smyth, H. F., Jr., C. P. Carpenter, and C. S. Weil.

Range-finding toxicity data, list III. J. Ind. Hyg. Toxicol.
31:60-62, 1949.

100. Smyth, H. P., Jr., C. P. Carpenter, and C. S. Weil.
Range-finding toxicity data: List IV. Arch. Ind. Hyg. Occup.
Med. 4:119-122, 1951.

101. Smyth, H. F., Jr., C. P. Carpenter, C. S. Weil, and U. C.
Pozzani. Range-finding toxicity data. List V. Arch. Ind. Hyg.
Occup. Med. 10:61-68, 1954.

102. Smyth, H. F., Jr., C. P. Carpenter, C. S. Weil, U. C. Pozzani,
and J. A. Streigel. Range-finding toxicity data. List VI. Am.
Ind. Hyg. Assoc. J. 23:95-108, 1962.

103. Sporn, A., I. Dinu, and V. Stanciu. The toxicity of
cinnamaldehyde. Igiena 14:339-346, 1965. (in Rumanian; English
abstract in Chem. Abstr. 64:10293a, 1966)

104. Stanford Research Institute. Profiles on Occupational Hazards
for Criteria Document Priorities, pp. [5-15]. Arlington,
Virginia: Stanford Research Institute, for U.S. Department of
Health, Education, and Welfare, National Institute for
Occupational Safety and Health, March 1977.

105. Steiner, P. E. , R. Steele, and F. C. Koch. The possible
carcinogenicity of overcooked meats, heated cholesterol,
acrolein, and heated sesame oil. Cancer Res. 3:100-107, 1943.

106. Stoner, G. D., M. B. Shimkin, A. J. Kniazeff, J. H. Weisburger,
E. K. Weisburger, and G. B. Gori. Test for carcinogenicity of
food additives and chemotherapeutic agents by the pulmonary
tumor response in strain A mice. Cancer Res. 33:3069-3085, 1973.

107. Suskind, R. R. , and V. A. Majeti. Occupational and
environmental allergic problems of the skin. J. Dermatol. 3:3,

1976. .

108. Teschke, R. , Y. Hasumura, and C. S. Lieber. Hepatic pathways of
ethanol and acetaldehyde metabolism and their role in the
pathogenesis of alcohol-induced liver injury. Nutr. Me tab. 21

(Suppl. 1) -.144-147, 1977.

109. Teuchy, H., J. Quatacker, G. Wolf, and C. F. Van Sumere.
Quantitative investigation of the hippuric acid formation in the
rat after administration of some possible aromatic and
hydroaromatic precursors. Arch. Int. Physiol. Biochim. 79:573,

1971.

110. Tittmar, H. G. Some effects of ethanol, presented during the
pre-natal period, on the development of rats. Br. J. Alcohol
Alcohol. 12:71-83, 1977. _

111. U.S. Department of Health, Education, and Welfare, Public Health
Service, Center for Disease Control, National Institute for
Occupational Safety and Health. National Occupational Hazard
Survey, conducted 1972-1974. Computerized data file. 1980.

112. U.S. Environmental Protection Agency, Office of Water
Regulations and Standards. Ambient Water Quality Criteria for
Acrolein. U.S. Environmental Protection Agency Report No. EPA
440/5-80-016. Washington, D.C.: U.S. Government Printing
Office, 1980. 100 pp.

255

113. Van Duuren, B. L. , L. Langseth, L. Orris, M. Baden, and M.
Kuschner. Carcinogenicity of epoxides, lactones, and peroxy
compounds. V. Subcutaneous injection in rats. J. Nat. Cancer
Inst. 39:1213-1216, 1967.

114. Venkatasetty, R. Genetic variation induced by radiation and
chemical agents in Drosophila melanogaster . Dissertation.
Bowling Green, Kentucky: Bowling Green State University, 1971.
138 pp.

115. Watanabe, P., and S. Sugimoto. Study on the carcinogenicity of
aldehyde. 3rd report. Four cases of sarcomas of rats appearing
in the areas of repeated subcutaneous injections of
acetaldehyde. GANN 47:599-601, 1956. (in Japanese)

116. Watanabe, T. , and D. M. Aviado. Functional and biochemical
effects on the lung following inhalation of cigarette smoke and
constituents. II. Skatole, acrolein, and acetaldehyde.
Toxicol. Appl. Pharmacol. 30:201-209, 1974.

117. Weber-Tschopp, A., T. Fischer, R. Gierer, and E. Grandjean.
Experimentally induced irritating effects of acrolein on
humans. Int. Arch. Occup. Environ. Health 40:117-130, 1977.

118. Williams. R. T. Detoxication Mechanisms. The Metabolism and
Detoxication of Drugs, Toxic Substances and Other Organic
Compounds. 2nd ed. New York: John Wiley & Sons, Inc., 1959.
796 pp.

CHAPTER 9
EFFECTS OF ALDEHYDES ON VEGETATION

For over 80 yr, formaldehyde was assumed to play an important role
in plant metabolism as the first product of photosynthesis. According
to the hypothesis of the German chemist von Baeyer, carbon dioxide
absorbed from the air was dissociated by green plants into carbon
monoxide that was reduced to formaldehyde, which in turn polymerized
to a carbohydrate. 10 However, experimental evidence never supported
this hypothesis. Researchers were unable to distill formaldehyde from
huge quantities of leaves or to enhance sugar production in leaves by
adding formaldehyde. As the concept of the essentiality of
formaldehyde in plants faded, the phytotoxic nature of the compound
began to emerge. Once Benson and Calvin had demonstrated that
3-phosphoglyceric acid was the first product of photosynthesis,
further interest in formaldehyde was focused on its phytotoxicity .

The greatest incentive for the investigation of aldehydes as a
class of compounds was probably the occurrence of photochemical smog
in California and other highly populated areas of the United States in
1945. Although hydrocarbons and oxides of nitrogen were suspected of
being the principal reactants in smog, 8 the specific pollutants
responsible for plant damage had not been identified. Several groups
of investigators experimentally subjected intact plants or plant parts
to known doses of artificially generated aldehydes and then described
symptom development or measured the impairment of some physiological
process.

In addition to these investigations related to ambient air
quality, i- 1 * *- n is two p i an t studies were prompted by reports of
the emission of formaldehyde vapors in confined areas under special
conditions. 17 23 In effect, growth chambers or seeding magazines
made of wood or particleboard were found to release formaldehyde that
proved to be injurious to seeds or seedlings stored in them. These
case histories one in the United States and the other in
Australia were reported 25 yr apart.

Finally, information on the response of plants to aldehydes has
been uncovered as a result of the use of aldehyde-containing compounds
in specific plant practices, such as postharvest treatment of fruit
and the collection of maple syrup.

It is the purpose of this chapter to assemble experimental data
from these diverse sources related to the effect of aldehydes on
vegetation. The material is critically reviewed with the intent of

256

257

arriving at a definitive statement regarding the phytotoxicity of
aldehydes.

There is wisdom in the maxim that "those who cannot remember the
past are condemned to repeat it." Before presenting information on
aldehydes, a rather "new" group of pollutants, we should consider two
models that have been painstakingly derived from studies of more
thoroughly investigated pollutants, such as ozone, sulfur dioxide, and
hydrogen fluoride.

The first is a conceptual model of factors that influence the
effects of air pollutants on vegetation (Figure 9-1) . This model was
adapted from an evaluation of the phytotoxicity of ozone and
photochemical oxidants. 16 The model shows that one must understand
many factors before one can predict the response of a plant species to
a specific pollutant. Those factors include genetic variability,
stage of plant development, climatic and edaphic factors, interactions
among pollutants, interactions among pathogens and insects, and
pollutant dosage. Plant responses are classified as visible or subtle
effects.

In a second model, plant responses are classified according to the
degree and type of effect produced at each level of biologic
organization, and an attempt is made to relate effects at the cellular
level with those anticipated at the level of the intact plant or plant
community (Table 9-1) . This model was used by the National Research
Council 15 to evaluate the effects of fluoride on vegetation.

ALDEHYDE IN AMBIENT AIR AND PLANT INJURY

The only report correlating aldehyde concentrations in ambient
air with plant injury was published by Brennan et al. x In New
Jersey, foliar symptoms in Snowstorm petunias (Petunia hybrida Vilma
"Snowstorm") were similar to those reported by Taylor et al. in the
field in California. 21 Leaves that were rapidly expanding in size
appeared water soaked between the veins; and after several hours in
sunlight, the upper leaf surfaces developed characteristic necrotic
bands, and the lower leaf surfaces, a glazed appearance. The youngest
leaves were marked only slightly, if at all, at the apex; and the
oldest leaves escaped injury. (According to Stephens et al. , 2
similar symptoms were experimentally induced in petunias with
irradiated ozone-olefin mixtures, irradiated nitrogen dioxide and
hydrocarbons, irradiated aldehydes, or peroxyacetylnitrate, PAN, which
was common to all irradiated nitrogen oxide mixtures.) The appearance
of symptoms could be correlated with increased concentrations of
aldehyde in ambient air on either of the previous two
days concentrations generally exceeding 0.20 ppm for 2 h or 0.30 ppm
for 1 h by the bisulfite test. Inasmuch as the oxidant concentration
in ambient air measured by a Mast sensor was lower than normal, the
researchers assumed that neither peroxyacetylnitrate nor ozone was
responsible for the injury to petunias. It was not established
whether there was a causal relationship, rather than correlation,
between aldehydes and plant damage.

258

NUMBER AND FREQUENCY
OF EXPOSURES

POLLUTANT
CONCENTRATION

DOSE

PRESENCE OF
OTHER POLLUTANTS

DURATION OF
EACH EXPOSURE

V

CLIMATE

SPECIES

SOIL

PLANT
RECEPTOR ~=

GENETIC
VARIABILITY

PATHOGENS

AGE

V

MECHANISM OF ACTION

EFFECTS

VISIBLE

SUBTLE

FIGURE 9-1 Conceptual model of factors involved in air-pollution effects on
vegetation. Adapted from National Research Council.-**

s

cu

4-1
CO

>,

co
O

o

w

4J

cd

CO

4-1

dcd

cd d

rH

4J CO

d cd -H

H N d

H cd

co d W)

4J Cd l-l

o oo o

CU r-l

14-1 O

i3 O

-d bO

0) O

y o

-d H

d so d

H cd

1 4-1 W)

4-) O H

d o

cd co

4J rH M

d CU

H >

rH CU CU

o J d

Oi CO

n co

4-1 d H

00 H

Cn

cu

a

4J

/">

CtJ

0-

a

d

cu

H CO

rH CU CO

H B CU

B >. ^

N -H

rH d rH

H 0) O

CU &

O d CO

4-1

-d <y

cu co a

}-l 4-

cu o -d

H

4-1 CU d

rH

(U

r-j 4-1 Cd
<i 4-1

^ W

d
o

H

4J d

cd o

rH H

H 4-1

S cd

H H

CO H

co a.

cd co

cu

T3 H

a>

CO Tj

cd cu

cu t-i

M cu

O 4J

(U rH

a <

s

o

4-1
H

-d

tered growth a
development

Modification of ce
organelles and
metabolism

I

SS

o

4J

0,

H

4-1

d

o

d

o -d

d

cu

g

d cd

H

3

d

4-1

CO O

O

4J

CU 'H

d

d

00 4-1

M

cd

d -H

4-1

H

cd co

CO

ex

&

d

o

H

4->

CO

4-1

O

CO

d

d

0)

cu

-d

d

S

o

4J

d

H

o

Qi

4-1

v-i

0)

H

V-l

-^

^

0)

d

*d

CO

cu

cu

cd

o

cu

n

r-l

o

-d

14-1

a

01

orotic

C

ay disruption

Pat

d
o

H
4-1

cd
o

H
4-1
H

-o

r-l

cd

3

rH

H
(U
O

Necrotic

A

4-1

cd
cu

t3
T3

d
cd

g^

H rH
4-1 CU
(X O

d

M 'I I

co o

H

Q

d
o

H
4-1

cd
H
O
CO

cu

Q

4J

d
cd

rH

a

M cd

o cu

r-l

4J 4-1

oj o

CU

Q

m

H

o

o

rH

cd
d
o

H

0)
4-1

o-

I

cd

259

260

In a later paper, the New Jersey investigators reported that 6-14
petunia-damaging episodes related to aldehydes occurred each year in
the state over a 4-yr period. The white petunias were generally
sensitive, the mixed white were intermediate, and the red, pink,
purple, and blue tended to be resistant. 2 In 1978, Lewis and
Brennan noted that the injury syndrome observed on petunias in the
field could be reproduced with a mixture of ozone and sulfur dioxide
in experimental fumigations. 12

EXPERIMENTAL FUMIGATIONS
VISIBLE PLANT INJURY CAUSED BY ALDEHYDES

In an effort to simulate the plant injury observed in California
as a result of so-called smog in the mid-1940s, Haagen-Smit ^t al. 8
exposed five plant species that appeared to be the most sensitive in
the field (spinach, endives, sugar beets, oats, and alfalfa) to a
variety of organic and inorganic compounds in a fumigation chamber at
concentrations generally less than 1 ppm. Several aldehydes were
among the compounds tested. Formaldehyde had little effect on the
test plants: exposure at 2 ppm for 2 h did not visibly affect any of
the species, and exposure at 0.7 ppm for 5 h produced a symptom only
in alfalfa (Table 9-2), and it was atypical. A 4-h exposure to
trichloroacetaldehyde at 0.8 ppm caused smoglike symptoms on
alfalfa speckled necrosis and marginal wilting of the leaves but did
not, damage the other species. Exposure to the unsaturated aldehyde,
acrolein, at 0.1 ppm for 9 h also produced symptoms on alfalfa
resembling natural smog damage, but there was no suggestion of damage
to the other species. Higher doses of acrolein (0.6 ppm for 3 h or 1.2
ppm for 4.5 h) produced numerous sunken pits on both surfaces of
spinach, endives, and beets, but the injury was unlike that observed
in the field. Having failed to reproduce typical smog symptoms on
four of the five sensitive plant species, the group of investigators
in California concluded that aldehydes were not responsible for plant
damage in the Los Angeles area.

In 1960, Darley et al. 3 had occasion to evaluate acrolein
effects on pinto beans as they were testing the phytotoxicity and
eye-irritation severity of varius ozone-hydrocarbon mixtures. They
reported damage to bean plants from exposures to acrolein at 2.0 ppm
for 70 min that, "while not severe, was definite and indistinguishable
from the underside bronzing typical of oxidant damage." It should be
noted that from 1940 to 1960 the term "oxidant damage" was used to
describe under-surface leaf injury that was later proved to be caused
by PAN.

, A more recent study by N. Masaru and K. Fukaya (personal
communication) indicated a greater phytotoxicity of acrolein than
previously reported. Experiments in Japan revealed that bean leaves
exposed to acrolein at 0.5 ppm developed brown foliar lesions after 4
h, and morning-glories developed similar symptoms after 6-7 h. Damage
was more severe if the plants were fumigated in wet, rather than dry,

<N
I

cd

CO
4J

d
cd

iH

CM

d
o

CO

cu

CO

cd
O

.3

S

CO

H
J-i

s

X!
4J

g

d
o

4-1
O

CO
4J
O
0)

14-1
14-1
w

cd

U-l

cd o << E-i

4-1

H H H

CO
4J O O O

cd
o

1

O O 1

4-1 ,
CO O O <

H O O <

<!

d
w

=1 rC

t*i O

i-l -H

d P-

M C/3

d /-x

H

H 2

4J >

2 rH O rv cs

O iH CO

fl > CN H
CO v-x

Hs

O (X
O P-

o o o

g*

d o
o M

^j i-l LO
rt p^

4-1 CO *
cd O <N LO *

s&

Q W

cO ON ^

x

H

cd

&

43

4J
H

0)
M

d

H

0)
00

fl

bO

CO

4J O

g

CO

1:

CO P<

W) >T.

Cd 4J

cd cd

33 <U

CO 00

a

o

H

cd TJ

4J bfl

o

M CO

3

d o

d
cd
00

H

0)

d

d

H
CU

iH
O
M
O

r cu
o o

M
H

<U
4-t

d

H
M

P.

o d
d -H

O H
43

261

262

conditions. Radish leaves did not respond until the acrolein exposure
was increased to 6-7 h at 1.5 ppm, and neither geraniums nor tomato
plants were affected even at the greater exposure. Thus, Masaru and
Fukaya demonstrated two principles that have been apparent when air
pollutants have been studied more extensively: species respond
differently to a given exposure to pollutant, and environmental
factors affect plant response.

VISIBLE PLANT INJURY CAUSED BY IRRADIATED ALDEHYDES

While the California group was considering an ozone-olefin
reaction as the probable source of eye irritation and plant damage,
Stephens _et al. l9 recognized that aldehydes were products of such
reactions. They irradiated selected aldehydes in static systems with
48 Blacklite fluorescent tubes that emitted radiation of wavelength
less than 3000 A. They then passed the aldehydes and their reaction
products over petunias and pinto bean leaves (8 or 14 d old) for 1-1.5
h (Table 9-3). The concentrations of aldehydes were 4.5-9.0 ppm at
the start of the fumigation and decreased to 1.5-4.5 ppm by the end of
the fumigation. Formaldehyde and acetaldehyde and their reaction
products caused little or no injury to the plants. Propionaldehyde
and butyraldehyde and their reaction products produced a glazing of
the lower surface of petunia leaves and of trifoliate and 8-d old
primary leaves of pinto beans, but did not injure 14-d old primary
leaves of the beans. Irradiated ozone-olefin mixtures or irradiated
nitrogen dioxide-hydrocarbon mixtures caused a similar response.

Speculating that small concentrations of nitrogen oxides may have
been present in the Stephens ejt al. fumigation, Hindawi and
Altshuller 9 investigated the phytotoxicity of irradiated
formaldehyde and propionaldehyde in the presence of low and high
concentrations of NO X (Table 9-4). The species that they tested
(petunias, tobacco, and pinto beans) were not affected by a
combination of formaldehyde at 6.1 ppm and NO X at 0.9 ppm for 4 h,
despite the generation of oxidant at 0.65 ppm. They speculated that
the oxidant was not ozone, but a nontoxic compound. The next higher
homologue, propionaldehyde, proved more toxic, causing injury to
plants at 0.52 ppm in the presence of NOx at 0.5 ppm. On the basis
of symptom type and species of plant affected, the researchers
identified the same five classes of injury that they had observed in
the same three plant species exposed to irradiated automobile
exhaust, in discussing the aldehydes, they expressed an opinion that
irradiated acetaldehyde did not cause significant damage, inasmuch as
Stephens et al. had observed no phytotoxicity with a mixture of
irradiated cis-2-butene and ozone, despite a high yield of
acetaldehyde. They also assumed that acrolein did not cause
significant damage to petunias, pinto beans, and tobacco leaves,
because there was no phytotoxicity in their own experiments with
irradiated mixtures of 1,3-butadiene and nitrogen oxide, although
acrolein at 1.0 ppm was formed as a product, it cannot be assumed,

263

TABLE 9-3
Plant Damage Caused by Four Irradiated Aldehydes

Concentration of
Aldehydes, ppm

A B C D

Duration of
Fumigation, h

Plant Injury
14-d-old 8-d-old
Pinto

17.7 15.8 8.5

17.9 16.0 8.3 2.8

14.6 13.8 6.9 3.8

12.5 11.8 6.3 2.5

17.5 16.5 8.2 4.5

22.0 21.4 9.0 3.6

11.2 10.6 5.1 1.7

16.0 12.0 6.5 1.5

14.4 8.9 4.5 1.6

Pinto Pinto Petunia
Butyraldehyde

1.5 Severe Severe

1 Severe Severe

Propionaldehyde

1.25 Severe Severe

1 Severe Severe

Acetaldehyde

100 Light

1 00

1.5 Light Light

Formaldehyde

0.25 Atypical

1 Atypical

19
Reprinted with permission from Stephens et al.

b A, in cell before irradiation; B, in cell after 2 h of irradiation with
black lights in static system; C, at beginning of plant fumigation,
after circulation through plant box; D, at end of fumigation.

60 d rH

_c

b^ ^ M

d d o

4J

CO
CO

S ^

3 cu
O ." >

d -H

0) f

cfl

> cfl

00

O -H

O 4J

u

oti

ri d

4-1 01

O -H 4J

u ex cu

"d S

st

co ex

43 T3

01

CO

o d

O 00

CO

M M

>4H CO

co cd

fl\ 1 1

S 3 x o o

on

d cu

QJ r|

d l

<N CO
O CO

O rH
H 43

^1

CO Cfl rH

U CO

r]

CO 43 U

o d

d) en

cfl O

cu o

rH 4J

ri n

H co
<J co
cd

x S x o o

.. (U
Cfl

M cfl

o cu
cj n

T Ci

01 CO 14-1

43 d

O U

O CO M

4J -H

CO Cfl 3

H

CO

<4H rH M

CO

CU CM

l-i U

d

J-l

d o

3 CO
4-1 CO

X ^
3 o

X S

CO 01
. CX

M cu ex

CU 3
CX cfl

O -H
H 4J
M Cfl
CU ^

p t ^j

CXMH

d

-d

3 H M
3 01

CU CU

n y

a) H

CO >

3 d

i i

CO CO

co o

cd ca

CU P 01

o y

:d S

I "rt *

8 S *J

CO ^

x d

CU O T3

CU -H

2 ^

O

43 "d

i_(

00 >

1 0)

MCd

CJ CO

st 4-1

CO

3 0) d

rH

> 0)

ja -d 43 cu
H a> M

* M 28

o \o m o o

> Cfl
>. CO CU
0) 43
rH
rH O

CO

rl 0)
Ol rl

t s^ Hi

CN| CN H O O CTi

CU 4J
CO 4J f3

O >>

H

3*1 3 C Q <3 rH

M

CO Cfl -H

T3 rH

cd a)

CU

cfl -H ex

Ol CO

W M

I Q

rH

rH rH
CO o T3

00 3
Ctf CO

so a; M o
<q 60 4- a

H e z Sod

2-g

Q *d CU r"

43

in in n' co

rH m O CN O 4J
rH

o o o o o <

"4-1 d
H Cfl

X 4-1

> o

Cfl T> O

cu d cfl

M 3
0)

> m
cfl

rH

0)

rl >1

Cd i <g
H

cd

43 cfl 43
O

M . !

0} 43

CO
4J CU CO

H

in U

d 3 cu

O> rH CO

4J ^

rH i> m H vo cd

n

S CO >-,

3 > rH

^W C\| d

ex, z ^

o o o o o d

H

cu *>co

4J d CO

!

M cd
4-1 cu d

d
d

CO Cfl rH
(-1 CU CJ

SCO Cfl
CU
H 43 y

cd

Q

*d

4J -H

c

s E

rrt

I m h
d; H cr m o ox w

>[* _.
;| d

H

O
g 4J QJ

d o

-H Cfl
X J-i

4J rl

d MH 4J

cd o cu

S s t

X O J-i

MJ

o a

r_j ex
H ex a

T

r? -ft

g bl

OJ -H C T

pq 4J o i-

(fl h c

O r<

I 4-1

CO
CO
H

i a

^ <u

S 1 1 1 vo H CX
II 1
31 j m vO 43

3 S

; x, little; ;
ower surface;
ves, upper su
pper surface.

from a Mast o
Multiplicatl
ained by colo

y c

13

CU H Cfl 3

4-1

S

CU

U CU

CO 43

H u i

1) 4-1

cfl iH

00 CU

P^ d d i

3 d

l-l CO CO

d TJ

o o

-H 4

ex

>, CM -H

c st m m i i w
D . . i l ex

4J CU 00 CU

H -H 0)

-d X co
cd o o

CO O 1

d <n en o i cu

rl CU O 0)

CU -H 43

Cfl M r

H P4

4J H >> rH

srf *"O ^j

cd;

o

264

265

however, that the phytotoxicity of an aldehyde in a complex mixture is
the same as when it occurs singly.

SUBTLE PLANT INJURY CAUSED BY ALDEHYDES

In addition to the investigations involving visible effects of
aldehydes on plants, there has been some experimental work on their
physiologic effects. Among the processes examined have been
photosynthesis, respiration, transpiration, and pollen germination.

Photosynthesis and Respiration

Researchers in Canada 1 * evaluated the effect of formaldehyde on
photosynthesis of an alga, Euglena gracilis. When they passed air
containing formaldehyde at 0.075 ppm through a 5-ml sample of euglena
in bicarbonate buffer for 1 h, the rates of photosynthesis and
respiration of the cells were slightly but not statistically
significantly reduced (Table 9-5). In fasted cells (those suspended
in buffer for 4.5 h before aldehyde exposure) the researchers noted
that formaldehyde might even have a beneficial effect. Propionaldehyde
at 0.100 ppm decreased the rates of photosynthesis and respiration of
euglena; again, fasting of the cells offered protection against the
toxic effects (Table 9-5) .

The notion that formaldehyde may be beneficial to algae is
consistent with the results of studies by Doman et al. 5 and Krall
and Tolbert, 11 who demonstrated that [ C] formaldehyde was
absorbed by leaves of kidney bean and barley plants and that in light
it was fixed rapidly in products similar to those formed from carbon
dioxide.

Transpiration

The effect of aldehydes on transpiration was evaluated by Fries et
al. 7 of Sweden. Having observed in a prior investigation that
ethereal oils in gaseous form reduced transpiration rates in leaves,
they proceeded to try to determine whether specific aldehydes were
responsible. They enclosed wheat seedlings in a cuvette through which
air containing a specific aliphatic aldehyde was passed for 1 h at a
constant flow rate, temperature, and relative humidity. All six
aliphatic aldehydes tested (trans-2-hexenal, pentanal, hexanal,
heptanal, octanal, and nonanal) at 1.0 yM (24 ppm) caused a decrease
in transpiration rate. Because the aldehyde treatment caused a
reduction in transpiration rate even greater than that caused by
complete darkness, there was some question whether the change was due
entirely to stomatal closure. Irrespective of the mechanism, Fries et
al. concluded that volatile aldehydes may play a role in the control
of transpiration of plants under field conditions. It would be

266

TABLE 9-5

Effect of Exposure to Formaldehyde (at 0.075 ppm for 1 h) and

Propionaldehyde (at 0.100 ppm for 1 h) on Rates of Photosynthesis

and Respiration of Euglena gracilis a

Rate b

Formaldehyde Propionaldehyde

Control Exposure Control Exposure

Unfasted cells

Photosynthesis 5.25 4.54 6.09 4.71

Respiration 2.26 1.83 2,18 1.85

Fasted cells

Photosynthesis 4.22 4.61 5.25 5.45

Respiration 1.47 1.54 1.75 1.66

a Reprinted with permission from deKoning and Jegier.^

b For photosynthesis, micromoles of oxygen given off by 6.3 x 10 6 cells
in 10 min; for respiration, micromoles of oxygen absorbed by 6.3 x 10^
cells in 10 min.

267

important to know whether the effect persisted after the removal of
the pollutant.

Pollen Germination

Pollen germination has proved sensitive to various air pollutants,
such as ozone. 6 The implication is that the inhibition of pollen
germination will be reflected as an adverse effect on reproductive
capacity of a species. In 1976, Masaru et al. 13 reported on their
examination of the effects of formaldehyde, acrolein, sulfur dioxide,
nitrogen dioxide, and ozone on lily pollen. They sowed pollen grains
on culture medium, placed the medium in a fumigation chamber with
pollutants at various concentrations, and measured pollen tube length
after 24 h (Table 9-6). A 5-h exposure to formaldehyde at 0.37 ppm
resulted in a significant reduction in pollen-tube length, whereas a
1- or 2-h exposure was innocuous. When formaldehyde was increased to
2.4 ppm, a 1-h exposure caused a decrease in tube length. The
investigators observed that, with respect to pollen, the activity of
formaldehyde was comparable with that of nitrogen dioxide. Acrolein
proved to be more injurious to pollen than any of the other pollutants
tested. At 0.40 ppm, acrolein caused a 40% decrease in pollen-tube
elongation after 2 h; at 1.70 ppm, it completely prevented extension
of the pollen tube. Having previously observed that exposure to
acrolein at 0.50 ppm for 6-7 h caused acute foliar injury to lily,
Masaru et^ al.. 13 concluded that lily pollen was as sensitive as
foliage to aldehyde treatment. Masaru et_ al. also tested combinations
of pollutants on lily pollen. Pollen grains exposed to sulfur dioxide
at 0.69 ppm for 30 min or to nitrogen dioxide at 0.15 ppm for 30 or 60
min showed little inhibition of tube elongation; if they were then
exposed to formaldehyde at 0.26 ppm, significant inhibition occurred
(Table 9-7).

PLANT EXPOSURES TO ALDEHYDES UNDER SPECIAL CONDITIONS
WOODEN CONTAINERS

Two reports of aldehyde damage to seedlings arose from similar
circumstances in the United States and Australia some 25 yr apart.
While culturing oat seedlings in a growth chamber made of ponderosa
pine and hardboard (Masonite Tempered Presdwood) , Weintraub and
Price 23 observed a marked retardation of seedling growth. Other
species including wheat, corn, sorghum, barley, tomato, bean,
lettuce, and radish were similarly affected. Hypothesizing that a
toxic agent was liberated from the box, they confined seeds under a
bell jar with small pieces of well-seasoned pine board or with
hardboard and again observed the inhibitory action. Nine other species
of wood were associated with the same effects. In an attempt to
identify the volatile compound, they placed vials of various compounds
in a desiccator containing oat seeds. The most inhibitory compounds

268
TABLE 9-6

Pollen-Tube Length of Lilium longiflorum after Exposure of
Pollen Grains to Various Pollutants a

Pollutant Gas
Sulfur dioxide

Nitrogen dioxide

Ozone

Formaldehyde

Acrolein

Pollutant

Concentration,

ppm

Pollen-Tube Length, % of
control, after Exposure
Lasting:

1 h

2 h

5 h

0.40

96.2

92.4

0.0

0.71

45.0

21.2

0.0

2.50

32.2

0.0

0.0

0.57

89.2

85.7

80.0

1.70

77.5

60.3

17.2

2.00

31.7

0.0

0.0

0.28

81.8

80.0

72.7

2.09

88.2

95.5

80.0

0.37

100.0

100.0

27.7

1.40

86.5

67.3

0.0

2.40

62.5

41.6

0.0

0.40

90.0

40.0

0.0

1.40

44.4

0.0

0.0

1.70

0.0

0.0

0.0

a Reprinted with permission from Masaru e_t al,

13

0)

H

ff
H

cn
cfl

o

01

Hcd
3 oj

CO O
O Cl

w cr
a)

H C/3

2 d

4H -H
tfl
CO

C

M CQ
O 4J

4-1
O

(30

ft
(U
,-1

S

r^vor^cNjoQOH-^cncMoo

OOCT\iHrHOCMp r loooOO

H g er.

mcofo^oocorooooooo

H rH

0)

H 4H

rH O

01 d

3

3* 4J

0) to

a n a i

3 S ^ '

! 3 S ! ! 8 S ! ! 8 g

-i

o

^

J

u

M

3 d

a o

-H

EX -U>

< 2

^ >O vO vO -^ >tf-

JJ 1

a d i

-

i i i i i i ^ *".

1 O O 1 1 O O 1 | O O

O

ace

1) O CX

o o a

A

a

o

4J O

oooooo ooooo

M a

d"

o

H

4J

cd

f-l CTi

irj LO

(3 ^

H 30

01 O

O rH

o

C B

o a

U Pi

01

u a)

3

o

j ^

H

X 4J -H

TJ

< a -d

d

1 (0

OJ

4J M
j 3 3

60

o at

o rH m

M a

1 H rH
H 3

4-1 O
H N

i PL, c/i

a o

0)

a.

269

270

proved to be acrolein, crotonaldehyde, hydrogen peroxide, crotonic
acid, and acrylic acid. Concentrations of the compounds were not
determined.

About 25 yr later, wheat-breeders experienced a similar problem in
using a magazine planting device made of bonded particleboard. If
seeds were stored in such a magazine for 1-3 d, the germination
percentage was reduced; if stored for 3 wk, the seeds completely fail
to germinate. 17 The authors suspected that free formaldehyde
released from the bonding resin of the particleboard was responsible
for the problem. They conducted a series of experiments with wheat in
contact with or at various distances from particleboard bonded with
urea-f ormaldehyde . After 1 d in a seeding magazine, the emergence
rate for seedlings started to decline; after 1.5 d, there was only 3%
emergence. If wheat seeds were stored in a paper bag at various
heights above the particleboard for 30 mo, all seeds within 7.5 cm of
the board were adversely affected. If the particleboard was cured for
5 d at 40C, the volatile substance was no longer released, and seeds
were not affected. The authors recommended that bonded particleboard
not be used in the construction of seeding magazines.

POSTHARVEST TREATMENTS

The literature of plant pathology contains information on two uses
of aldehydes that provide additional data on plant effects.
Acetaldehyde vapor at concentrations far in excess of ambient
exposures has been used to prevent postharvest decay of strawberries
caused by Botrytis cinerea and Rhizopus stolonifer . 18 Exposure to
1% acetaldehyde vapor prevented decay and had no adverse effect on
quality (as indicated by total solids and pH) of the berries. Exposure
to 4% acetaldehyde produced objectionable results, decreasing the
quality and injuring the caps of the berries.

MAPLE-SYRUP COLLECTION

Paraf ormaldehyde pills have been used on tapholes drilled into
sugar maple trees to increase or prolong the yield of sap.
Apparently, par af ormaldehyde temporarily inhibits the growth of
microorganisms in the taphole that would normally restrict sap flow.
Walters and Shigo 22 studied the long-range effect of such
treatment. They treated some 200 mature sugar maple trees with a
250-mg paraformaldehyde pill for 2 mo and harvested selected trees
over a 35-mo period. They found a higher incidence of discolored or
decayed wood in the treated trees than in the controls.
Paraformaldehyde altered the vascular and ray systems that play an
important role in vessel plugging of trees and thereby facilitated
invasion by wood-decaying fungi.

271
DISCUSSION

To what extent does the information on aldehydes satisfy the two
models (Figure 9-1 and Table 9-1) and approximate the impact of this
class of pollutants on vegetation? Inspection of Figure 9-1 reveals
that a cluster of factors related to the plant receptor and another
cluster related to pollutant dosage determine the nature and degree of
plant response likely to be elicited by a given pollutant.

With regard to the factors influencing the plant receptor,
investigations involving air pollutants, such as ozone and fluoride,
have emphasized that genetic makeup is foremost in determining the
sensitivity or tolerance of a plant. Well over 100 plant species, as
well as many groups of cultivars of some 20 species have been tested
for their reactions to ozone and fluoride, and lists of plants that
are highly sensitive, of intermediate or slight sensitivity, or
resistant to each pollutant have been compiled. In contrast, only 15
species have been tested for sensitivity to aldehydes; the only
results on intraspecif ic variations were those related to petunias in
the ambient-air study conducted in New Jersey.

In addition to the genetic component, the stage of plant
development influences the response of a plant receptor. Most
frequently, it is the vegetative parts, rather than the fruit or
floral parts, that exhibit toxicity symptoms, although there are
exceptions, such as peach fruit injury due to fluoride. The age of
the tissue is critical. For example, plants at an age associated with
nearly complete expansion of leaves are at their peak of ozone
sensitivity, but are past their peak of PAN sensitivity. The stage of
maximal sensitivity to aldehydes has not been determined, although
there is a clue in the greater susceptibility of young bean leaves
than of old leaves. Many species must be tested to determine the part
of their life cycle when injury is most likely.

The sensitivity of a plant receptor is also influenced by many
climatic and edaphic factors. Some of the climatic factors that have
been important with respect to more thoroughly investigated air
pollutants are temperature, relative humidity, light quality and
intensity, photoperiod, and rate of air movement. None of these has
been systematically evaluated in aldehyde fumigations. Masaru et a^. ,
however, did observe that wet leaves were injured more than dry
leaves. Among the edaphic factors that influence the growth and
development of the plant receptor and hence the response to a
pollutant are soil moisture, aeration, and nutrients. None of these
has been evaluated in aldehyde studies.

Finally, biotic factors have been found to alter a plant
receptor. Research with ozone has demonstrated that the presence of a
pathogen in a plant may increase or decrease ozone phytotoxicity.
Information of this nature on aldehydes is lacking.

Turning from the factors that act directly on the receptor, it is
necessary to consider the factors that are involved in the dose
component. According to Figure 9-1, pollutant concentration, duration
of exposure, and number of exposures are important. Obviously, a high
dose of pollutant is more apt to be injurious than a low dose.

272

Although it is not self-evident, it may also be true for some
aldehydes, as it is for ozone, that a given dose applied over a short
period produces a greater plant reponse than the same dose applied
over a long period. An acute exposure may, in fact, evoke a response
different from that to a chronic exposure, depending on the mechanism
of action of the pollutant and the mechanism of resistance of the
plant. In aldehyde research, excluding the work with particleboard
containers, exposures have been short (1-6 h) . Concentrations of
aldehydes used with higher plants generally have ranged from 0.2 to
2.0 ppm. Because the investigators used analytic techniques of varied
sensitivity and precision for measuring aldehydes (Table 9-8), it is
futile to attempt to compare their results. (Methods for aldehyde
determination are presented in Chapter 6) . Indeed, whether the
concentrations used in experimental work are realistic, with respect
to those occurring in ambient air, will not be known until there is a
refined standard method for use in experimental and ambient
atmospheres. In a sense, history would be repeating itself, in that
methods for ozone (oxidant) determination have progressed through a
series of "acceptable" techniques since the toxicity of ozone was
first recognized. Even assuming the availability of better analytic
techniques, one must recognize that aldehydes are present in complex
mixtures with other pollutants that may also be phytotoxic and
interact with the aldehydes. In 1966, Menser and Heggestad 111
established that administration of mixtures of sulfur dioxide (0.50
ppm) and ozone (0.03 ppm) for 2 h caused 23% foliar injury on tobacco,
whereas administration of the gases separately produced no injury.
This type of experimentation has not been done with aldehydes, except
that of Masaru et al_. , 13 who observed that exposure to sulfur
dioxide or nitrogen dioxide, followed by exposure to formaldehyde,
resulted in greater inhibition of pollen germination than did
exposoure to either pollutant singly. Exposure to formaldehyde after
ozone exposure appears to decrease pollen-tube length, but the
differences were not significant.

Inspection of the second model reveals the need for assessing
air-pollution effects on plants at many levels of biologic
organization, including cell, tissue, organism, and ecosystem.
Ideally, one would know whether any of the structural or functional
alterations initiated at the cellular level are expressed at any of
the higher levels. For example, are the changes in rates of
photosynthesis and respiration responsible for foliar lesions in an
intact leaf? Does the presence of a necrotic or chlorotic lesion have
an important effect on the plant in toto? Is growth or yield
reduced? Does injury to individual plants constitute a threat to the
ecosystem? These questions cannot yet be answered with respect to
the aldehydes the available information is too sparse.

273

TABLE 9-8
Analytic Methods for Aldehydes Used in Plant Studies

Compound

Aldehydes (including
acrolein)

Acrolein

Acrolein

Aldehydes
Aldehydes
Formaldehyde

Formaldehyde,
propionaldehyde

Method

Gravimetric precipitation of dimedons
or 2,4-dinitrophenyl hydrazones

Absorption in buffered semicarbazide
hydro chloride solution and reading on
s pec tropho tome ter

Absorption in 0.1 N hydroxylamine
hydrochloride solution and measurement
by m-aminophenol method

Bisulfite addition
Long-path infrared cell
Chromotropic acid

3-Methyl-2-benzothiazolone hydrazone
test

Reference
8

13

1

21
13

4

274
REFERENCES

1. Brennan, E. f I. A. Leone, and R. H. Dames. Atmospheric aldehydes
related to petunia leaf damage. Science 143:818-820, 1964.

2. Brennan, E. , I. A. Leone, R. H. Daines, and A. Mitlehner.
Polluted petunias. Florists' Rev. 139 (3599) :29, 75-76, 1966.

3. Darley, E. P., J. T. Middle ton, and M. J. Garber. Plant damage
and eye irritation from ozone-hydrocarbon reactions. Agric. Food
Chem. 8:483-485, 1960.

4. deKoning, H., and Z. Jegier. Effect of aldehydes on
photosynthesis and respiration of Euglena gracilis. Arch.
Environ. Health 20:720-722, 1976.

5. Doman, N. G. , A. K. Romanova, and Z. A. Terent'eva. Conversion of
some volatile organic substances absorbed by leaves from the
atmosphere. Doklady Akad. Nauk S.S.S.R. 138:702, 1961. (in
Russian)

6. Feder, W. A. Reduction in tobacco pollen germination and tube
elongation, induced by low levels of ozone. Science 160:1122,
1968.

7. Fries, N., K. Flodin, J. Bjurman, and J. Parsby. Influence of
volatile aldehydes and terpenoids on the transpiration of wheat.
Naturwissenschaften (Berlin) 61:452-453, 1974.

8. Haagen-Smit, A. J., E. F. Darley, M. Zaitlin, H. Hull, and W. M.
Noble. Investigation on injury to plants from air pollution in
the Los Angeles area. Plant Physiol. 27:18-34, 1952.

9. Hindawi, I. J., and A. P. Altshuller. Plant damage caused by
irradiation of aldehydes. Science 146:540-542, 1964.

10. Kostychev, S. P. Chemical Plant Physiology. Philadelphia: P.
Blakiston's Sons and Co., 1931. 354 pp.

11. Krall, A. R., and N. E. Tolbert. A comparison of the light
dependent metabolism of carbon monoxide by barley leaves with that
of formaldehyde, formate and carbon dioxide. Plant Physiol.
32:321-326, 1957.

12. Lewis, E., and E. Brennan. Ozone and sulfur dioxide mixtures
cause a PAN-type injury to petunia. Phytopathology 68:1011-1014,
1978.

13. Masaru, N. , F. Syozo, and K. Saburo. Effects of exposure to
various injurious gases on germination of lily pollen. Environ.
Pollut. 11:181-187, 1976.

14. Menser, H. A., and H. E. Heggestad. Ozone and sulfur dioxide
synergism: Injury to tobacco plants. Science 153:424-425, 1966.

15. National Research Council, Committee on Biologic Effects of
Atmospheric Pollutants. Effects of fluoride on vegetation, pp.
77-133. In Fluorides. Washington, D.C.: National Academy of
Sciences, 1971.

16. National Research Council, Committee on Medical and Biologic
Effects of Environmental Pollutants. Plants and microorganisms,
pp. 437-585. In Ozone and Other Photochemical Oxidants.
Washington, D.C.: National Academy of Sciences, 1977.

17. O'Brien, L., and R. A. Orth. An unexpected cause of poor
germination and emergence of wheat. Crop Sci. 18:510-512, 1978.

275

18. Prasad, K. f and G. J. Stadelbacher . Effect of acetaldehyde vapor
on postharvest decay and market quality of fresh strawberries.
Phytopathology 64:948-951, 1974.

19. Stephens, E. R. , E. F. Darley, and 0. C. Taylor. Air Pollution
Research at University of California, Riverside. An Interim
Report on the Cooperative Program between William E. Scott and
Associates, Perkasie, Pa., and the University of California,
Riverside. Prepared for meeting of Research Advisory Committee
Smoke and Fumes Committee, American Petroleum Institute, held at
Riverside, California, October 1-2, 1959.

20. Stephens, E. R. , E.F. Darley, 0. C. Taylor, and W. E. Scott.
Photochemical reaction products in air pollution. Int. J. Air
Water Pollut. 4:79-100, 1961.

21. Taylor, O. C., E. R. Stephens, E. F. Darley, and E. A. Cardiff.
Effect of air-borne oxidants on leaves of the pinto bean and
petunia. Proc. Amer. Soc. Hort. Sci. 75:434-444, 1960.

22. Walters, R. S., and A. L. Shigo. Discolouration and decay
associated with paraformaldehyde-treated tapholes in sugar maple.
Can. J. Forest Res. 8:54-60, 1978.

23. Weintraub, R. L., and L. Price. Inhibition of plant growth by
emanations from oils, varnishes, and woods. Smithson. Misc.
Collect. 107(17) :1-13, 1948.

CHAPTER 10
EFFECTS OF ALDEHYDES ON AQUATIC ORGANISMS

This chapter presents an overview of current knowledge of the
effects of aldehydes on aquatic organisms. It addresses 39 aldehydes ,
which were considered to be potentially more hazardous to aquatic life
than other aldehydes by having been identified in water, having been
produced or consumed in the United States in amounts of at least 1
million pounds per year, having been used as pesticides, or being
currently considered by EPA as high-priority water pollutants. These
aldehydes are listed in Table 10-1.

Of the 39 aldehydes, 36 have been identified in water, including
industrial and sewage-treatment plant discharges, surface waters, and
drinking water (see Chapter 5); the 36 comprise 10 of the 11
high-production or high-consumption aldehydes and all the pesticide
aldehydes except metaldehyde. Only two aldehydes acrolein and endrin
aldehyde are currently considered by EPA to be high-priority water
pollutants. The reason for so classifying endrin aldehyde is unclear;
it may be a transformation product of the pesticide endrin.

TOXIC ITY TO AQUATIC ORGANISMS

Very little is known about the toxicity of most of these
potentially hazardous aldehydes to aquatic organisms. Eighteen have
been evaluated for toxicity, but only one has been evaluated for
chronic toxicity and bioconcentration potential. Median tolerance
limits (e.g., LC 5 QS and ECsos) have been reported for seven; the
remaining 11 have been evaluated only for selective piscicidal
activity.

ACROLEIN

Of all the aldehydes that have been evaluated for toxicity to
aquatic organisms, acrolein is the most toxic. For fish, the LC$Q
for exposure periods of 24-144 h ranges from 0.046 to 0.24 ppm (Table
10-2) . Aquatic invertebrates appear to be as sensitive as fish.
Butler 7 estimated the 48-h LCso for a marine shrimp (Penaeus
azteca) to be 0.1 ppm. He also estimated that exposure at 0.055 ppm
for 96 h would reduce the growth rate of oysters (Crassostrea

276

277

TABLE 10-1
Aldehydes Potentially Hazardous to Aquatic Organisms

Identified
in Water 3

X (ESD)
X (ESD)
X (ES)
X (ESD)
X (ESD)
X (S)
X (SD)
X (S)
X (D)
X (SD)

X (D)
X (S)

X (S)
X (SD)
X (SD)

X (D)
X (S)
X (E)
X (ED)
X (D)
X (D)
X (ED)
X (S)
X (D)

X (ESD)
X (D)
X (S)
X (ESD)
X (D)
X (E)
X (E)
X (E)
X (S)
X (D)
X (ES)
X (E)

High Pro-
duction or
Consumption

X
X
X
X
X

Pesti-
cide

X
X

Aldehyde

Acetaldehyde

Acrolein b

Anisaldehyde

Benzaldehyde

Butyraldehyde

Capraldehyde

Caproaldehyde

Caprylaldehyde

Chloral b

Cinnamaldehyde

Citronellal

Crotonaldehyde

Di~tert-butylhydroxy-

4-benzaldehyde
Dichlorobenzaldehyde
Dimethylbenzaldehyde
Enanthaldehyde b
Endrin aldehyde
2-Ethylbutyraldehyde
2-Ethylcaproaldehyde
Formaldehyde
Furaldehyde b
Isobutyr aldehyde
Isopropionaldehyde
Isovaleraldehyde
Mesitaldehyde
Me thacrolein b
Met aldehyde

2-Methylpropionaldehyde
3-Me thyl valeraldehyde
Nonylaldehyde
Par aldehyde
Propionaldehyde b
Sallcylaldehyde b
Sorbaldehyde
Syringaldehyde
Undecylaldehyde
Valeraldehyde
Vanillin 5
Veratraldehyde b

a E industrial or sewage treatment plant effluent; S = surface water;
D = drinking water.

b Evaluated for toxicity.

LPA

Priority

Pollutant

278

TABLE 10-2
Acute Toxicity of Acrolein to Fish

Exposure
Species LC qn , ppm Time, h Reference

Oncorhynchus tschawytscha 0.08 24 5

(king salmon)

Salmo gairdnerii 0.065 24 5

(rainbow trout)

Salmo trutta 0.046 24 6

(brown trout)

Lepomis macrochirus 0.10 96 19

(bluegill sunfish)

Micropterus salmoides 0.16 96 19

(largemouth bass)

Amia calva 0.062 24 19

(bowfin)

Pimephales promelas 0.084 144 20

(fathead minnow)

Gambusia af finis 0.061 48 19

(mosquito fish)

Fundulis similis 0.24 48 7

(longnose killifish)

279

virginica) by 50%. For the water flea (Daphnia magna), Macek and
co-workers 20 reported a 48-h LC5Q of 0.057 mg/L.

Studies by the Shell Development Company l have shown acrolein
to be lethal to various aquatic flora such as Hydrodictyon sp.,
Spirogyra sp. , Potomogeton sp. , Zannichellia sp. , Cladophera sp., and
Ceratophyllum sp. at concentrations ranging from 1.5 to 7.5 ppm.

Macek and co-workers 20 evaluated acrolein for chronic effects in
the water flea (p_. magna) and the fathead minnow (Pimephales promelas)
with the flow-through exposure technique, which provides for
continuous replacement of the test solutions in the exposure tanks.
They also based their toxicity estimates on measured acrolein
concentrations. The water flea was exposed at five concentrations,
from 0.0032 to 0.043 mg/L, for 64 d (three generations). Although the
compound had no statistically significant effect on fecundity at the
concentrations tested, it significantly reduced survival at 0.034 and
.043 mg/L.

In the chronic test with minnows, the test concentrations ranged
from 0.0046 to 0.042 mg/L, and the test was begun with 27-d-old fish.
None of the tested concentrations affected the growth, survival, or
reproductive capacity of these fish; however, at 0.042 mg/L, the
compound significantly reduced the survival of their offspring.

The EPA has determined that acrolein has acute and chronic toxic
effects on freshwater aquatic organisms at concentrations as low as
0.068 and 0.021 mg/L, respectively, and acute toxic effects on marine
organisms down to 0.055 mg/L. 32 There are no data on chronic
toxicity in sensitive marine organisms. Toxic effects would occur at
lower concentrations among species that are more sensitive than those
tested.

FORMALDEHYDE

Kitchens and co-workers 18 reviewed all the available published
information on formaldehyde as an environmental pollutant. They
discussed the structure and chemical and physical properties of
formaldehyde, its production and uses, the sources of environmental
formaldehyde, monitoring and analytic methods, and its human health
and environmental effects. Much of the aquatic toxicologic
information presented by Kitchens and associates was from a review by
Schnick 30 of the toxicity of formalin.

Formalin has been evaluated for acute toxicity with a variety of
fish, amphibians, invertebrates, and algae. Schnick 's review 30
presented LC 50 s for 20 freshwater and marine fish. A comparison of
the 24-h LC 50 s (the most common reported) showed striped bass
(Morone saxitalis) to be the most sensitive of the fish tested. The
24-h LC 50 of formalin for that species was 10-30 yl/L (3.7-11.1
mg/L as formaldehyde). Young fish were more sensitive than older
fish. For the other species tested, the 24-h LC 50 s ranged from
about 50 to 120 rag/L as formaldehyde.

Formalin is probably the most widely used agent for treating fish
for ectoparasitic infections and fish eggs for fungal infections. 33
Treatment is usually very short, but frequently repetitive. The

280

recommended concentration for treating ectoparasitic infections is
formaldehyde at about 160-250 mg/L applied in the water for 1 h/d for
up to 3 d. With fish reared in ponds, formalin is added to the pond to
achieve a formaldehyde concentration of 5-9 mg/L and permitted to
dissipate naturally. To treat eggs with fungal infections, much
higher concentrations are used (about 620 mg/L); however, the exposure
period is reduced to 15 min/d. These treatment schedules indicate that
fish and fish eggs can tolerate concentrations considerably higher
than the 24-h LCsQS, but for only short periods.

In bullfrog tadpoles exposed to formalin at 275-325 yl/L (about
100-120 mg/L as formaldehyde) for 48 h, 20-30% mortality has been
reported; ll * however, 100% mortality has been observed in bullfrog
tadpoles exposed for 72 h to formalin at as low as 40 yl/L (15 mg/L
as formaldehyde) and in tadpoles of the leopard frog (Rana pipiens)
and toad (Bufo sp.) exposed at 30 and 50 yl/L (11 and 18.5 mg/L as
formaldehyde), respectively. ** l "* * 7 At a concentration of 100
yl/L (37 mg/L as formaldehyde) , formalin was not toxic to larvae of
the salamander, Amblystoma tigrinum in 72 h. 11 * In toxicity tests
with the freshwater invertebrate Daphnia magna, mortality occurred at
formalin concentrations as low as 13.5 yl/L (5 mg/L as
formaldehyde). 26 In a review by McKee and Wolf, 23 the median
threshold concentration for formaldehyde was reported to be 2 mg/L for
Daphnia sp. (2-d exposure). Helms lk reported observing no effect in
crayfish (Procambarus blandingi) exposed to formalin at up to 100
yl/L for up to 72 h.

Gellman 1 2 estimated the toxic concentration of formaldehyde for
aerobic aquatic microorganisms to be between 130 and 175 mg/L, and
Hermann 15 found that 740 mg/L inhibited their oxygen utilization by
50%.

Helms 11 * observed no effect in the aquatic algae Aphanothece sp.,
Oscillatoria sp. f and Rhizoclonium sp. exposed for 7 d to formalin at
up to 100 yl/L (37 mg/L as formaldehyde). However, cultures of
Scenedesmus sp., Sirogonium sp., Spyrogyra sp., and Stigeoclonium sp.
did not survive at concentrations of 15 yl/L (5.6 mg/L as
formaldehyde) or higher. Euglena gracilis, exposed to formaldehyde at
0.075 ppm for 1 h, showed reduced photosynthesis and respiration, 16
but the reduction in photosynthesis was not statistically significant.

OTHER ALDEHYDES

Table 10-3 presents acute-toxicity estimates reported for
acetaldehyde in two species of fish, a shrimp, and two species of
algae. Unpublished studies performed by the Dow Chemical Company
(R.J. Moolenau, personal communication) on acetaldehyde showed 70 ppm
to be lethal to fathead minnows (Pimephales promelas) in 96 h;
however, exposure for 96 h at 60 ppm caused no toxic effect.
Acetaldehyde thus appears to be acutely lethal over a very narrow
concentration range.

For furaldehyde, Middlebrooks and co-workers, 21 * using the
harlequin fish (Rasbora heteromorpha) , determined the 24- and 48-h

281

TABLE 10-3
Acute Toxicity of Acetaldehyde to Acquatic Organism

Concentration,
Species Statistic mg/L Reference

Lagodon rhomboides 24-h LC^Q 70 11

(pinfish)

Lepomis macrochirus 9b-h LC^Q 53 8

(bluegill sunfish)

Crangon crangon 24-h LC^Q >100 29

(shrimp)

Nitzchia linearis 5-d EC 5Q (growth) 237 1

(alga)

Navicula seminulum EC 5Q (growth) 239 28

(alga)

282

LC5QS to be 31 and 23 ppm, respectively. Mattson and co-workers 22
reported a 96-h LC 50 of 32 ppm for the fathead minnow (P.
promelas) . With the bluegill sunfish (L. macrochirus), Turnbull and
co-workers 31 determined the 24- and 48-h ^598 of furaldehyde to
be 32 and 24 mg/L, respectively. In very turbid water, the 24-h
LC5Q for bluegills has been reported as 44 mg/L, and the 48- and
96-h LC 50 s both have been determined to be 24 mg/L. 31 * The
lowest reported 96-h LC 50 of furaldehyde is 1.2 ppm, 35 for
bluegills.

Dawson and co-workers 9 tested crotonaldehyde and propionaldehyde
with bluegill sunfish (L. macrochirus) and tidewater silversides
(Menidia beryllina) . The 96-h LCsQS of crotonaldehyde for the
bluegill and silversides were 3.5 and 1.3 mg/L, respectively. The
96-h LC5QS of propionaldehyde were 130 mg/L for the bluegill and 100
mg/L for the silversides.

According to Mattson and co-workers, 22 the 96-h 1^59 of
vanillin for fathead minnows is 112-121 mg/L, on the basis of two
tests. Palmer and Maloney 27 determined the toxicity of vanillin to
six species of algae with concentrations up to 2 mg/L. This
concentration slightly inhibited the growth of Gomphonema sp., but had
no effect on the other species. In a search for a chemical agent that
would selectively kill the Oregon squawfish (Ptychocheilus
oregonensis) , MacPhee and Ruelle 21 screened nearly 1,900 compounds,
including five aldehydes, for toxicity to the squawfish, steelhead
trout (Salmo gairdnerii) , Chinook salmon (Oncorhynchus tschawytscha) ,
and coho salmon (Oncorhynchus kisutch) . Each compound was evaluated
at only one concentration. Some of the compounds were tested with
only some of the species. Compounds that caused death, loss of
equilibrium, or other signs of distress were considered toxic. At 10
ppm, anisaldehyde was toxic to all the species. At 1 ppm, polymeric
butyraldehyde was toxic to chinook salmon, but not to the other
species. At 10 ppm, chloral (as chloral hydrate) had no effect on any
of the species; however, at the same concentration, mesitaldehyde was
toxic to the squawfish, steelhead trout, and coho salmon (the chinook
salmon was not used as a test species). At 2.5 ppm, none of the
species was affected by salicylaldehyde.

Applegate and co-workers 2 performed a similar study on about
4,400 chemical compounds (including 13 aldehydes) to find one that
would selectively affect the marine lamprey (Petromyzon marinus) .
Other fish included in the study were the rainbow trout (Salmo
gairdnerii) and the bluegill sunfish (Lepomis macrochirus). With some
of the compounds, tests with the trout and bluegill were deleted. The
test concentrations were 0.1, 1.0, and 5.0 ppm, and the maximal
exposure time was 24 h. At 5 ppm, acrolein had no effect on any of
the species. This result is not in agreement with those presented
earlier. Other aldehydes that had no effect on any of the species at
5 ppm were anisaldehyde, benzaldehyde, butyraldehyde (polymer),
chloral, dichlorobenzaldehyde, enanthaldehyde, isobutyraldehyde,
metacrolein, propionaldehyde, salicylaldehyde, and veratraldehyde. Of
the aldehydes tested, only mesitaldehyde was toxic to the lamprey at 5
ppm; it was not tested with the other fish species.

283

Neither of these studies showed chloral to have any effect at up
to 10 ppm (10 mg/L) . That is surprising, because the recommended
concentration for producing anesthesia in fish is about 2-3 mg/L, 3
at which concentration narcosis usually occurs in less than 5 min.

BIOCONCENTRATION

Bioconcentration is the process by which a chemical becomes more
concentrated in an organism than it is in the environment of the
organism. 25 Chemicals that bioconcentrate are generally considered
to be more hazardous than those which do not, because, at sublethal
concentrations, they may eventually produce toxic effects as the body
burden increases or may cause a progressive increase in the body
burden of organisms at higher trophic levels as the compound is
transferred through food webs or chains.

The propensity of a chemical to bioaccumulate can be determined
experimentally by exposing an organism to it and determining the
concentrations of the compound in the tissues and in the exposure
medium. The ratio of these two concentrations is called the
bioconcentration factor (BCF) . Of the 39 aldehydes addressed in this
chapter, acrolein is the only one for which a BCF has been
experimentally derived. The value was 344, and it was determined with
the bluegill sunfish (S. Petrocelli, personal communication).

An indirect method of determining the propensity of a chemical to
accumulate in tissues is to determine its octanol-water partition
coefficient, which is an experimentally derived ratio of the
concentrations of a compound in N-octanol and in water after N-octanol
is mixed with water that contains the compound. The logarithms of the
octanol-water partition coefficients for the 36 aldehydes are shown in
Table 10-4. The log P values were calculated by the method of Hansch
and Leo, 13 except that for acrolein, which was determined
experimentally (Petrocelli, personal communication) . Hydration will
reduce the calculated log P values of the aliphatic aldehydes by 0.38
and will increase the values of the aromatic aldehydes by 0.39. Of
the log P values shown, capraldehyde, caprylaldehyde,
3 , 5-di-tert-butyl- 4-hydroxybenzaldehyde, mesitaldehyde,
nonylaldehyde , and undecylaldehyde have values over 3.0. These may
bioconcentrate appreciably in aquatic organisms.

284
TABLE 10-4

Logarithms of Octanol-Water Partition Coefficients
for 36 Aldehydes 3

Aldehyde L 8 P

Acetaldehyde -0.21

Acrolein - 9 ^

Anis aldehyde 1 ' 54

Benzaldehyde 1 - 48

Butyr aldehyde 0.87

Capraldehyde 4 ' 1;L

Caproaldehyde 1.95

Caprylaldehyde 3 * 03

Chloral ' 51

Cinnaraaldehyde 1<92

Crotonaldehyde ' 55

3 , 5-Di-tert-butyl-A-hydr oxybenzaldehyde 4.75

Dichlorobenzaldehyde 2.00

Dimethylbenzaldehyde 2.82

Enanthaldehyde 2>49

2 -Ethyl but yr aldehyde 1 73

2-Ethylcaproaldehyde 2.81

Formaldehyde -0.87

Furaldehyde - 88

Isobutyr aldehyde 0.65

Tsopropionaldehyde 1.82

Is ovaler aldehyde 1.28

Mesitaldehyde 3 - 48

Methacrolein - 33

2-Methylpropionaldehyde 0.65

3-Methylvaleraldehyde 1 82

Nonylaldehyde 3.57

Paraldehyde 1.15

Propionaldehyde 0.33

Salicylaldehyde I- 89

Sorbaldehyde i- 08

Syringaldehyde 2.15

Undecylaldehyde 4 65

Valeraldehyde 1.41
Vanillin - 89

Veratr aldehyde ! 61

a Calculated by the method of Hansch and Leo, 13 except the value
for acrolein, which was experimentally derived (S. Petrocelli,
personal communication).

285
REFERENCES

1. Academy of Natural Sciences. The Sensitivity of Aquatic Life to
Certain Chemicals Commonly Found in Industrial Wastes. Final
Report. Washington, D.C.: U.S. Public Health Service, 1960. 89 pp.

2. Applegate, V. C., J. H. Howell, A. E. Hall, Jr., and M. A. Smith.
Toxicity of 4,346 Chemicals to Larval Lampreys and Fishes. U.S.
Department of the Interior Fish and Wildlife Service Special
Scientific Report Fisheries No. 207. Washington, D.C.: U.S.
Department of the Interior, 1957. 157 pp.

3. Bell, G. R. A Guide to the Properties, Characteristics, and Uses
of Some General Anaesthetics for Fish. Fisheries Research Board
of Canada Bulletin No. 148. Ottawa: Roger Duhamel, F.R.S.C.,
Queen's Printer and Controller of Stationery, 1964. 4 pp.

4. Bennett, G. W. Management of Lakes and Ponds. 2nd ed. New York:
Van Nostrand Reinhold Company, 1971. 375 pp.

5. Bond, C. E., R. H. Lewis, and J. L. Fryer. Toxicity of various
herbicidal materials to fishes, pp. 96-101. In C. M. Tarzwell,
Compiler. Biological Problems in Water Pollution. Transactions
of the 1959 Seminar. Robert A. Taft Sanitary Engineering Center
Technical Report W60-3. Cincinnati, Ohio: U.S. Department of
Health, Education, and Welfare, Public Health Service, Robert A.
Taft Sanitary Engineering Center, 1960.

6. Bur dick, G. E., H. J. Dean, and E. J. Harris. Toxicity of aqualin
to fingerling brown trout and bluegills. N.Y. Fish Game J.
11:106-114, 1964.

7. Butler, P. A. Effects of herbicides on estuarine fauna.
Proc. South. Weed Conf. 18:576-580, 1965.

8. Cairns, J., Jr., and A. Scheier. A comparison of the toxicity of
some common industrial waste components tested individually and
combined. Prog. Fish Cult. 30:3-8, 1968.

9. Dawson, G. W. , A. L. Jennings, D. Drozdowski, and E. Rider. The
acute toxicity of 47 industrial chemicals to fresh and salt water
fishes. J. Hazardous Mater. 1:303-318, 1977.

10. Ferguson, F. F., C. S Richards, and J. R. Palmer. Control of
Australorbis glabratus by acrolein in Puerto Rico. Public Health
Rep. 76:461-468, 1961.

11. Garrett, J. T. Toxicity investigations on aquatic and marine
life. Public Works J. 88:95-96, 1957.

12. Gellman, I. Studies on the biochemical oxidation of sewage,
industrial wastes, and organic compounds. Thesis. Water Pollut.
Abstr. 27:1859, pp. 307-313, 1954.

13. Hansch, C., and A. Leo. Chapter 4. The fragment method of
calculating partition coefficients. In Substituent Constants for
Correlation Analysis in Chemistry and Biology. New York: Wiley-
Interscience, 1979.

14. Helms, D. R. use of formalin for selective control of tadpoles in
the presence of fishes. Prog. Fish Cult. 29:43-47, 1967.

15. Hermann, E. R. Toxicity index for industrial wastes. Ind. Eng.
Chem. 51:84A-87A, 1959.

286

16. Hill, R. D. The use of acrolein, acrylaldehyde:2-propenal in the
treatment of submerged weeds in farm ponds. Ohio Agnc. Exp.
Stn. , 1960. 3 pp.

17. Kemp, H. T., J. P. Abrams, and R. C. Overbeck. Water Quality
Criteria Data Book. Vol. 3. Effects of Chemicals on Aquatic
Life. Selected Data from the Literature through 1968. U.S.
Environmental Protection Agency Project No. 18050 GWV05/71.
Washington, D.C.: U.S. Government Printing Office, 1971. 528 pp.

18. Kitchens, J. E. , R. E. Casner , G. S. Edwards, W. E. Harward III,
and B. J. Macri. Investigation of Selected Potential
Environmental Contaminants: Formaldehyde. U.S. Environmental
Protection Agency Report No. EPA-560/2-76-009 . Washington, D.C.:
U.S. Environmental Protection Agency, Office of Toxic Substances,
1976. 217 pp.

19. Louder, D. E., and F. G. McCoy. Preliminary investigations of the
use of aqualin for collecting fishes, pp. 240-242. In Proceedings
of the 16th Annual Conference, Southeastern Association of Game
and Fish Commissioners. New Orleans: Southeastern Association of
Game and Fish Commissioners, 1962.

20. Macek, K. J., M. A. Lindberg, S. Sauter , K. S. Buxton, and P. A.
Costa. Toxicity of Four Pesticides to Water Fleas and Fathead
Minnows. Acute and Chronic Toxicity of Acrolein, Heptachlor,
Endosulfan, and Trifluralin to the Water Flea (Daphnia magna) and
the Fathead Minnow (Pimephales promelas) . U.S. Environmental
Protection Agency Report No. EPA-600/3-76-099, 1976. Washington,
D.C.: U.S. Government Printing Office, 1976. 68 pp.

21. MacPhee, C., and R. Ruelle. Lethal effects of 1888 chemicals upon
four species of fish from western North America. Univer. Idaho
For. Wildl. Range, Exp. Stn., Bull. No. 3, 1969. 112 pp.

22. Mattson, V. R. , J. W. Arthur, and C. T. Walbridge. Acute Toxicity
of Selected Organic Compounds to Fathead Minnows. U.S.
Environmental Protection Agency Report No. EPA-600/e-76-097 .
Washington, D.C.: U.S. Government Printing Office, 1976. 12 pp.

23. McKee, J. E. , and H. W. Wolf, Eds. Water Quality Criteria. 2nd
ed. The Resources Agency of California, State Water Quality
Control Board Publication No. 3-A. Sacramento: State Water
Quality Control Board, 1963. 548 pp.

24. Middlebrooks, E. J., M. J. Caspar, R. D. Caspar, J. H. Reynolds,
and D. B. Porcella. Effects of Temperature on the Toxicity to the
Aquatic Biota of Waste Discharges. A Compilation of the
Literature. PRWG Report 105-1. Washington, D.C.: U.S. Department
of the Interior, 1973. 170 pp.

25. National Research Council, Environmental Studies Board.
Principles for Evaluating Chemicals in the Environment.
Washington, D.C.: National Academy of Sciences, 1975. 454 pp.

26. Nazareuko, J. V. Effect of formaldehyde on aquatic organisms.
Tr. Vses. Gidrobiol. Ova. 10:170, 1960. (in Russian)

27. Palmer, C. M. , and T. E. Maloney. Preliminary screening for
potential algicides. Ohio J. Sci. 55:1-8, 1955.

28. Patrick, R., J. Cairns, Jr., and A. Scheier. The relative
sensitivity of diatoms, snails, and fish to twenty common

287

constituents of industrial wastes. Prog. Fish Cult. 30:137-140,
1968.

29. Portmann, J. E., and K. W. Wilson. Toxicity of 140 Substances to
the Brown Shrimp and Other Marine Animals. Shellfish Information
Leaflet No. 22. Burnham-on -Couch, Essex, England: Ministry of
Agriculture, Fish, and Food; Fisheries Laboratory, 1971. 12 pp.

30. Schnick, R. A. Formalin as a therapeutant in fish culture. U.S.
Fish and Wildlife Service Report FWS/LR-74/09. Springfield,
Virginia: National Technical Information Service, Publication No.
PB-237 198, 1973. 175 pp.

31. Turnbull, H. , J. G. DeMann, and R. F. Weston. Toxicity of various
refinery materials to fresh water fish. Ind. Eng. Chem.
46:324-333, 1954.

32. U.S. Environmental Protection Agency, Office of Water Regulations
and Standards. Ambient Water Quality Criteria for Acrolein. U.S.
Environmental Protection Agency Report No. EPA 440/5-80-016.
Washington, D.C.: U.S. Government Printing Office, 1980. 100 pp.

33. U.S. Fish and Wildlife Service, Bureau of Sport Fisheries and
Wildlife. Fish Disease Manual. Region 3. 1971. 183 pp.
Available from National Fisheries Center, Kearneysville, W. Va.

34. Wallen, I. E. , W. C. Greer, and R. Lasater . Toxicity to Gambusia
af finis of certain pure chemicals in turbid waters. Sewage Ind.
Wastes 29:695-711, 1957.

35. Wilber, C. G. The Biological Aspects of Water Pollution.
Springfield, Illinois: Charles C Thomas, 1969. 296 pp.

APPENDIX
Properties, Uses, and Synonyms of Selected Aldehydes

KEY TO TABLES A-l AND A-2
Aldehyde Entry in Tables A-l and A-2

p-Ac e t al de hy de

Acetaldol

Acetic aldehyde

Acetylformaldehyde

Acetylformyl

Acrolein

Acrylaldehyde

Acrylic aldehyde

AgriStrep

Aldehyde B

Aldehyde C-7

Aldehyde C-8

Aldehyde C-10

Aldehyde C-12

Aldehyde M.N.A.

Aldesan

Aldol

Allyl aldehyde

Amylcinnamaldehyde

a-Amylcinnamaldehyde

a-Arayl-3-phenylacrolein

Anhydrous chloral

m-Anisaldehyde

-Ani sal de hy de

p-Anisaldehyde

2-Anisaldehyde

4-Ani saldehyde

-Anisic aldehyde

^-Anisic aldehyde

Antifoam-LF

Aqualin

Artificial almond oil

Aub epine

Benzaldehyde-2 , 4-disulfonic

acid

Benzaldehyde FFC
Benzaldehyde-j>-sulfonic acid

sodium salt
Benzeneacetaldehyde
Benzenecarb onal
Benzenecarb oxaldehyde
-Benzenedicarboxaldehyde
Benzoic aldehyde

ACETALDEHYDE, Par aldehyde

BUTANAL, 3-Hydroxy-

ACETALDEHYDE

PROPANAL, 2-Oxo-

PROPANAL, 2-Oxo-

2 -PRO PENAL

2-PROPENAL

2 -PRO PENAL

STREPTOMYCIN sulfate

PROPANAL, a-Methyl-4-(l-methyl-

ethyl)benzene-
n-HEPTANAL
OCTANAL
DECANAL
DECANAL, Do-
UNDECANAL, 2-Methyl-
1 , 5-PENTANED1AL
BUTANAL, 3-Hydroxy-
2-PROPENAL

HEPTANAL, 2-(Phenylmethylene)-
HEPTANAL, 2-(Phenylmethylene)-
HEPTANAL, 2-(Phenylmethylene)-
ACETALDEHYDE, Trichloro-
BENZALDEHYDE, 3-Methoxy-
BENZALDEHYDE, 2-Methoxy-
BENZALDEHYDE, 4-Methoxy-
BENZALDEHYDE, 2-Methoxy-
BENZALDEHYDE, 4-Methoxy-
BENZALDEHYDE, 2-Methoxy-
BENZALDEHYDE, 4-Methoxy-
OCTANAL
2-PROPENAL
BENZALDEHYDE
BENZALDEHYDE, 4-Methoxy-
BENZ ALDEHYDE , 4-F ormy 1-1 , 3-

benzenedisulfonic acid
BENZALDEHYDE
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid sodium salt
ACETALDEHYDE, Benzene
BENZALDEHYDE
BENZALDEHYDE

1 , 4-BENZENEDICARBOXALDEHYDE
BENZALDEHYDE

289

290

Be nzylacet aldehyde

Benzylideneacetaldehyde

Biformal

Biformyl

Bourbonal

Butal

But aldehyde

n- But anal

Butanaldehyde

trans-2-Butenal

Butyl aldehyde

jQ-Butyl aldehyde

p-tert-Butylbenzaldehyde

4-tert-Butylbenzaldehyde

_t-Butylcarboxaldehyde
4-tert-Butylcyclohexane-

carboxaldehyde
_t-Butylfonnaldehyde
4-tert-Butylhexahydro-

benz aldehyde
p-tert-Butyl-g-methylhydr o-

cinnamaldehyde
Butyral
Butyraldehyde
n-Butyr aldehyde
Butyric aldehyde
Butyrylaldehyde
BVF

PROP ANAL, Benzene-

2-PRO PENAL, 3-Phenyl-

ETHANEDIAL

ETHANEDIAL

BENZALDEHYJJE, 3-Ethoxy-^f-

hydroxy-
BUTANAL
BUTANAL
BUT ANAL
BUTANAL
2-BUTENAL
BUTANAL
BUTANAL
BE NZ ALDEHYDE,

ethyl)-
BENZ ALDEHYDE,

ethyl)-

PROPANAL, 2,2-Dimethyl-
CYCLUHJiXAlvlJiCARBOXALDEHYDE s

(1,1-Dinethylethyl)-
PROPANAL, 2,2-Dimethyl-
CYCLOHEXANECARBOXALDEHYDE .

(1,1-Dimethylethyl)-
PROPANAL, 4-(l,l-Dimethylethyl)'

a~methylbenzene-
BUTANAL
BUTANAL
BUTANAL
BUTANAL
BUTANAL
FORMALDEHYDE

4-(l,l-Dimethyl-
4-(l,l-Dimethyl-

4-
4-

Capraldehyde

Capric aldehyde

Caprinaldehyde

Caprinic aldehyde

Caproaldehyde

n-Caproaldehyde

Caproic aldehyde

Capronaldehyde

Caprylaldehyde

ii-Caprylaldehyde

Caprylic aldehyde

Carbomethene

Cassia aldehyde

Chloral

-Chlorobenzaldehyde

_p_-Chlorobenzaldehyde

DECANAL

DECANAL

DECANAL

DECANAL

HEXANAL

HEXANAL

HEXANAL

HEXANAL

OCTANAL

OCTANAL

OCTANAL

ETHENONE

2-PROPENAL, 3~Phenyl-

ACETALDEHYDE , Trichloro-

BENZALDEHYDE, 2-Chloro-

BENZALDEHYDE, 4-Chloro-

291

4-((2-Chloroethyl)ethylamino)-

jD-tolualdehyde
j>-((2-Chloroethyl)methylamino)-

benzaldehyde
Cinnamal
Cinnamaldehyde
Cinnamic aldehyde
Cinnamyl aldehyde
Citral

Citronellal hydrate
Citronelloxyacetaldehyde

Coniferaldehyde
-Coniferaldehyde
Coniferyl aldehyde

Crategine
Crotonal
Crotonaldehyde
Crotonic aldehyde
Crotylaldehyde
Cumaldehyde
Cumene aldehyde
Cumic aldehyde
Cuminal

-Cuminal dehy de
Cuminic aldehyde
Cuminyl aldehyde
Cyclalia
Cyclamal

Cyclamen aldehyde

3-Cyclohexen-l-aldehyde
Cyclohexene-4-carboxaldehyde
Cyclosia
p-Cymene-7-carboxaldehyde

Decaldehyde

n-Decaldehyde

n-De canal

Decanal de hyde

Decyl aldehyde

n-Decyl aldehyde

Decylic aldehyde

-2-Deoxy-2-(methylamino)-a-l-gluco-
pyranosyl-(l-4)-N,N/-bis(amino-
iminome thyl ) D-s tr ep tamine

Diethylacetaldehyde

BENZALDEHYDE, 4-( (2-Chloro-

ethyl)ethylamino)-2-met:hyl-
BENZALDEHYDE, 4( (2-Chlo roe thyl) -

methylamino)-
2-PROPENAL, 3-Phenyl-
2-PROPENAL, 3-Phenyl-
2-PROPENAL, 3-Phenyl-
2-PROPENAL, 3-Phenyl-
2,6-OCTADIENAL, 3,7-Dimethyl-
OCTANAL, 7-Hydroxy-3,7-dimethyl-
ACETALDEHYDE, 3, 7-Dimethyl-6-

octenyloxy-
2-PROPENAL, 3-(4-Hydroxy-3-

methoxyphenyl)-
2-PROPENAL, 3-(4-Hydroxy-3-

me t ho xy pheny 1 ) -
2-PROPENAL, 3-(4-Hydroxy-3-

methoxyphenyl)-
BENZ ALDEHYDE, 4-Methoxy-
2-BUTENAL
2-BUTENAL
2-BUTENAL
2-BUTENAL

BEUZALUEUYDE, 4-( 1-Methylethyl)-
ACETALDEHYDE, a-Methylbenzene-
BENZALDEilYDE, 4- (1-Me thyl ethyl )-
BENZALDEHYDE, 4-(.l-Methyiethyl)-
BENZALDEHYDE, 4-(l-Methylethyl)-
BENZALDEHYDE, 4- (1-Me thy le thyl )-
BENZALDEHYDE, 4-(l-Methylethyl)-
OCTANAL, 7-Hydroxy-3 , 7-dimethyl-
PROPANAL , o-Methyl-4-( 1-methyl-

ethyl)benzene-
PROPANAL, a-Methyl-4-(l-methyl-

ethyl)benzene-

3-CYCLOHEXENE-l-CARBOXALDEHYDE
3- C YCLOHEXE NE-1 -C ARBO XALDEHY DE
OCTANAL, 7-Hydroxy-3,7-dimethyl-
ACETALDEHYDE , 4-(l-Methylethyl)-

benzene-
DE CANAL
DECANAL
DECANAL
DECANAL
DECANAL
DECANAL
DECANAL
STREPTOMYCIN

BUT ANAL, 2-Ethyl-

292

j>-(Diethylamino)benzaldehyde

Diformyl

1 , 4-DIformylbenzene

Dihyd rocinnamaldehyde

( 1 , 3-Dihydro-l , 3 , 3-triraethyl-2H-
indol-2-ylidene)-acetaldehyde

3 , 4-Dihydroxybenzaldehyde
methylene ketal

3, 4-Dimethoxybenzenecarbonal

3,5-Dimethoxy-4-hydroxybenzaldehyde

3 , 5-Dimethoxy-4-hydroxybenzene

carbonal

Dimethyl acet aldehyde
a , 4-Dimethylbenzeneacetaldehyde

3 , 4 -Dime thylenedioxybenzaldehyde

2 , 6-Dimethyl-5-hepten-l-al
3 , 7-Dimethyl-7-hydroxyoctanal
3 , 7-Dimethyl-6-octenal
3 , 7-Dimethyl-6-octenyl-oxy-

acetaldehyde
6 , 10-Dimethyl-3-oxa-9-undecanal

a, a-Dimethylpropanal
a, a-Dimethylpropionaldehyde
2 , 2-Dimethylpropionaldehyde
2 , 4 -Disulf obenz aldehyde

^i-Dode canal
1 -Do dec anal
Dodecanaldehyde
Dodecyl aldehyde
ja-Dodecyl aldehyde
Dodecylic aldehyde

BENZ ALDEHYDE, 4-(Diethylaiaino)-

ETHANEDIAL

1 , 4-BENZENEDICARBOXALDEHYDE

PROPANAL, Benzene-

ACETALDEHYDE, 1 , 3, 3-Trimethyl-A-

(2,ot)-indoline-
1 , 3-BENZODTOXOLE-5-CARBOX-

ALDEHYDE

BENZALDEHYDE, 3,4-Dimethoxy-
BENZALDEHYDE, 4-Hydroxy-3,5-

dimethoxy-
BENZALDEHYDE, 4-Hydroxy-3,5-

dimethoxy-
PROPANAL, 2 -Methyl -
ACETALDEHYDE, a ,4-Dimethyl-

benzene-
1 ,3-BENZODIOXOLE-5-CARBOX-

ALDEHYDE

HEPTENAL, 2,6-Dimethyl-5-
OCTANAL, 7-Hydroxy-3,7-diraethyl-
CITRONELLAL (d_ isomer)
ACETALDEHYDE, 3, 7 -Dimethyl -6-

octenyl-oxy-
ACETALDEHYDE, 3,7-Dimethyl-6-

octenyl-oxy-
PROPANAL, 2,2-Dimethyl-
PROPANAL, 2,2-Dimethyl-
PROPANAL, 2,2-Diraethyl-
BENZALDEHYDE , 4-Formyl-l , 3-

benzenedisulfonic acid

DECANAL, DO-
DECANAL, Do-
DECMAL, DO-
DECANAL, DO-
DECANAL, DO-
DECANAL, Do-

Enanthal

E nan thai dehyde

Enanthic aldehyde

Enanthole

Epihydrinaldehyde

2 , 3-Epoxypropanal

2 , 3-Epoxypropionaldehyde

Ethanal

Ethanedione

1 , 2-Ethanedione

n-HEPTANAL

n-HEPTANAL

n-HEPTANAL

n-HEPTANAL

OXIRANECARBOXALDEHYDE

OXIRANECARBOXALDE HYDE

OXIRANECARBOXALDEHYDE

ACETALDEHYDE

ETHANEDIAL

ETHANEDIAL

293

Ethavan
Ethovan
4-E thoxy-m-ani s aide hyde

Ethoxybenzaldehyde
jr-Ethoxybenzaldehyde
3~Ethoxy-a-ketobutyr aldehyde
Ethyl aldehyde
a-Ethylbutyr aldehyde
2-Ethylbutyr aldehyde
2-Ethylbutyric aldehyde
Ethylprotal

Ethylvanillin

BEUZ ALDEHYDE, 3-bthoxy-4-

hydroxy-
BENZALDEHYDh, J-Ethoxy-4-

hydroxy-
BENZALDEHYDE, 4-Ethoxy-3-

methoxy-

BENZALDEHYDE, 4-Ethoxy-
BENZALDEHYDE, 4-Ethoxy-
BUTANAL, 3-Ethoxy-2-oxo-
ACETALDEHYDE
BUT ANAL, 2-Ethyl-
BUTANAL, 2-Ethyl-
BUTANAL, 2-Ethyl
BENZALDEHYDE, 3-Ethoxy-4-

hydroxy-
BENZALDEHYDE, 3-Ethoxy-4-

hydroxy-

Fannofonn
Ferul aldehyde

Fisher's aldehyde

Fixol

Flomine

Flo-Mor

Formaldehyde solution

Formaldehyde trimer

Formalin

Formalith

Formic aldehyde

Formol

-Formylanisole

-Formylbenzaldehyde

4-Eormylbenzaldehyde

a-Formylbenzene acetic acid

4 Formyl-m-benzenedisulfonic acid
o_-Formylbenzenesulfonic acid

o_-Formylbenzenesulfonic acid

sodiiim salt
5-Formyl-l ,3-benzodioxole

2 Formyl butane

1 Formyl-3-cyclohexene

4 -Fo rmyl eye lohexene

-Formyl-N;,N-diethylaniline

FORMALDEHYDE

2-PROPENAL, 3-(4-Hydroxy-3-

me thoxyphenyl )-
ACETALDEHYDE , 1,3,3-Tnraethyl-A-

(2,a)-indoline-

OCTANAL, 7-Hydroxy-3,7-dimethyl-
HEPTANAL, 2-(Phenylraethylene)-
FORMALDEHYDE , Para-
FORMALDEHYDE

FORMALDEHYDE, 1 ,3,5-Trioxane
FORMALDEHYDE
FORMALDEHYDE
FORMALDEHYDE
FORMALDEHYDE
BENZALDEHYDE, 4-Methoxy-
BE NZENED ICARBOXALDEHYDE , 1,4-
1 ,4-BENZENEDICARBOXALDEHYDE
ACETALDEHYDE , a-Formylbenzene

acetic acid
BENZALDEHYDE, 4-Formyl-l,3-

benzenedisulfonic acid
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid sodium salt
1 , 3-BENZODIOXOLE-5-CARBOX-

ALDEHYDE

BUTANAL (dl), 2-Methyl-
3-CYCLOHEXE NE-1 -C ARBOXALDEHYDE
3-CYCLOHEXENE-l-CARBOXALDEHYDE
BENZALDEHYDE, 4-(Diethylamino)-

294

2-Formylf uran
5-Formylguaiacol

6 -Fo rraylguaiacol

a-Formyliso butyl benzene
4-Formyl-2-methoxyphenol

6-Formyl-2-methoxyphenol

2-(Formylmethylene)-l,3,J-trimethyl-

indoline
3-Formyl-2-methylindole

1 -Fo rmy 1-2-napht ho 1

2-Fo nny Ipen t ane
3-Fo rmylpentane
jn-Fo rraylphenol
cr-Formyl phenol
jo-Formylphenol
2-Formylphenol
3-Fonnylphenol
a-Formylphenylacetic acid

2-Formylpyridine

-Fo rrayl t o lue ne

2 -Formyl toluene

3-Formyl toluene

Fural

Fur aldehyde

a -Fur aldehyde

2-Fur aldehyde

Fur ale

2-Fur anal dehyde

Furancarbonal

2-Fur ancarbonal

Furfural

2-Furfural

Furfuraldehyde

2-Fur fur aldehyde

Furfurole

Furfurylaldehyde

Furole

a-Furole

2-Furylaldehyde

Fyde

BE NZ ALDEHYDE
BENZALDEHYDE
BENZ ALDEHYDE
BENZALDEHYDE

2-FURANCARBOXCALDEHYDE
BENZALDEHYDE, 3-Hydroxy-4-

methoxy-
BENZ ALDEHYDE, 2-Hydroxy-3-

methoxy-

BUTANAL, 3-Methyl-2-phenyl-
BENZ ALDEHYDE, 4-Hydroxy-3-

methoxy-
BENZALDEHYDE, 2-riydroxy-3-

methoxy-
ACETALDEHYDE, i,3,3-Trimethyl-A-

(2,a)indoline-
INDOLE-3-CARBOXALDEHYUE, 2-

Methyl-lH-
2-Hyd r oxy- 1 -NAPHTHALENECARBOX-

AL DEHYDE

PENT ANAL, 2-Methyl-
BUTANAL, 2-Ethyl-
BENZALDEHYDE, 3-Hydroxy-
2-Hydroxy-
4 -Hydro xy-
2-Hydroxy-
3-Hydroxy-
ACETALDEHYDE, a -Formyl benzene

acetic acid

2-PYRIDINECARBOXALDEHYDE
BENZALDEHYDE, 4-Methyl-
BENZALDEHYDE, 2-Methyl-
BENZALDEHYDE, 3-Methyl-
2-FURANCARBOXALDEHYDE
2-FURANC ARBOXAL DE HYDE
2-FURANCARB OXALDEHYDE
2-F URANC ARBOXALDE HYDE
2-FURANCARBOXALDEHYDE
2-FURANCARBOXALDEHYDE
2 -FURANC ARE OXALDE HYDE
2-FURANCARBOXALDEHYDE
2 -FURANCARBOXALDEHYDE
2-FURANCARBOXALDEHYDE
2-FURANCARBOXALDEHYDE
2-FURANCARBOXALDEHYDE
2-FURANCARBOXALDEHYDE
2-FURANCARBOXALDE HYDE
2-FURANCARBOXALDEHYDE
2-FURANCARBOXALDEHYDE
2-FURANCARBOXALDEHYDE
FORMALDEHYDE

Gallaldehyde 3,5-dimethyl ether

BENZALDEHYDE, 4-Hydroxy-3,5-
dimethoxy-

295

Geliotropin

Geranial

Ge rani aldehyde

Glutaral

Glut ar aldehyde

Glutardialdehyde

Glutaric dialdehyde

Glycidal

Glyc id aldehyde

Glyoxal

Glyoxal aldehyde

Glyoxylaldehyde

1 , 3-BENZODIOXOLE-5-
CARBOXALDEHYDE

2,6-OCTADIENAL, 3, 7 -Dime thy 1-
2,6-OCTADIENAL, 3,7-Dimethyl-
1,5 -PENT ANEDIAL
1,5-PENTANEDIAL
1,5-PENTANEDIAL
1,5-PENTANEDIAL
OXIRANECARBOXALDEHYDE
OXI RANECARBOXALDE HYDE
ETHANE DIAL
ETHANEDIAL
ETHANE DIAL

Heliotropin
Heliotr opine

Hende canal

Hendecanaldehyde

Heptaldehyde

n-Hept aldehyde

Heptanal

Heptanaldehyde

_n-Heptylaldehyde

2,4-Hexadien-l-al

Hexaldehyde

n-Hexanal

(E)-2-Hexenal

trans-Hex-2-enal

2- 1 r an s -Hexen al

t :r ans- 2-Hexenal

trans-2-Hexen-l-al

a-n-Hexyl cinnam al dehyd e

Hexyl cinnatnic aldehyde

Hexylenic aldehyde

a-n-Hexyl- 3-phenylacrolein

Hospex

Hyacinthal

Hyacinthin

Hydratropa aldehyde

Hydratropaldehyde

Hydratropic aldehyde

Hydrocinnamaldehyde

Hydrocinnamic aldehyde

2-Hydroxy-m-anisaldehyde

3 -Hydr oxy--anis aldehyde

1 , 3-BENZODIOXOLE-5-CARBOX-

ALDEHYDE
1 , 3-BENZODIOXDLE-5-CARBOX-

ALDEHYDE
UNDE CANAL
UNDE CANAL
_n-HEPTANAL
n-HEPTANAL
ri-HEPTANAL
n-HEPTANAL
n-HEPTANAL
2,4-HEXADIENAL
HEXANAL
HEXANAL
HEXENAL, 2-
HEXENAL, 2-
HEXENAL, 2-
HEXENAL, 2-
HEXENAL, 2-

OCTANAL, 2-(Phenylmethylene)-
OCTANAL, 2-(Phenylmethylene)-
HEXENAL

OCTANAL, 2-(Phenylmethylene)-
1,5-PENTANEDIAL
ACETALDEHYDE, ot-Methylbenzene-
ACETALDEHYDE, Benzene
ACETALDEHYDE, ct-Methylbenzene-
ACKTALDEHYDE, ot-Methylbenzene-
ACETALDEHYDE, ct-Methylbenzene-
PROPANAL, Benzene-
PROPANAL, Benzene-
BENZ ALDEHYDE, 2-Hydroxy-3-

methoxy-
BENZ ALDEHYDE, 3-Hydroxy-4-

methoxy-

296

4-Hydroxy-m-anisaldehyde

in-Hydroxyben zaldehyde

o-Hydroxybenzaldehyde

jD-Hydroxybenzaldehyde

g-Hydroxybutanal

Hydroxycitronellal

7-Hydroxycitronellal

4-Hydroxy-3,5-diraethoxy-

cinnamaldehyde
4-Hydr oxy-3-e thoxyben zaldehyde

jD-Hydroxy-m-methoxybenzaldehyde
4 -Hyd r oxy-3-me thoxycinnamal deh yde

4-(4-Hydroxy-4-methylpentyl)-A -
tetrahydrobenz aldehyde

2-Hydroxynaphthaldehyde
2 -Hyd roxy-a-naphth aldehyde
2-Hydroxy-l-naphthaldehyde
2 -Hydr oxy- 1-naphthyl aldehyde

BE1JZ ALDEHYDE, 4-Hydroxy-3-

methoxy-

BENZALDEHYDE, 3-Hydroxy-
BENZALDEHYDE, 2-Hydroxy-
BENZ ALDEHYDE, 4-Hydroxy-
bUTANAL, 3-Hydroxy-
OCTANAL, 7-Hydroxy-3,7-diraethyl-
OCTANAL, 7-Hydroxy-3,7-dimethyl-
2-PRO PENAL, 3-(4-Hydroxy-3,5-

diraethoxyphenyl)-
BENZALDEHYDE, 3-Ethoxy-4-

hydroxy-
BENZALDEHYDE, 4-Hydroxy-3-

methoxy-
2 -PRO PENAL, 3-(4-Hydroxy-3-

methoxyphenyl)-
3-CYCLOHEXENE-l-CARBOXALDEHYDE ,

4-(4-Hydroxy-4-methyl-

pentyl)-
NAPHTHALENECARBOXALDEHYDE, 2-

Hydroxy-1-
NAPHTHALENECARBOXALDEHYDE, 2-

Hydroxy-1-
NAPHTHALENECARBOXALDEHYDE, 2-

Hydroxy-1-
NAPHTHALENECARBOXALDEHYDE, 2-

Hydroxy-1-

Isobutanal
Isobutenal
Isobutyr aldehyde
Isodihydrolavandulyl aldehyde

Isopentanal

Isophthal aldehyde

Isopropyl aldehyde

jp_-Isopropylbenzaldehyde

4-Isopropylbenzaldehyde

Isopropyl formaldehyde

2-Isopropylidene-5-tnethyl-4-hexenal

j>-Isopropyl-a-ciethylhydro-

cinnam aldehyde
(^-Isopropylphenyl)acetaldehyde

3-(4-Isopropylphenyl)-2-methyl-

propanal
j^-Isopropylphenyl-a-methyl-

propyl aldehyde
Isovaleral

PROPANAL, 2-Methyl-
2-PROPENAL, 2-Methyl-
PROPANAL, 2-Methyl-
HEXENAL, 5-Methyl-2-(l-methyl-

ethylidene)4-
BUTANAL, 3-Methyl-
BENZENEDICARBOXALDEHYDE, 1,3-
PROPANAL, 2-Methyl-
BENZ ALDEHYDE, 4- (1 -Methyl ethyl ;-
BENZALDEHYDE, 4-(l-Methylethyl>
PROPANAL, 2-Methyl-
HEXENAL, 5-tfethyl-2-(l-methyl-

ethylidene)4-
PROPA14AL, a-Methyl-4-(l-

me thyl ethyl) benzene-
ACETALDEHYDE, 4-(l-Methylethyl)-

benzene-
PROPANAL, a-Methyl-4-

( 1 -me thyl ethyl )benze ne-
PROPANAL, a-Methyl-4-

(l-methylethyl)benzene-
BUTAHAL, 3-Methyl-

297

Isoval e raldehyde
Isovaleric aldehyde
Isovanillin

Ivalon

BUTANAL, 3-Methyl-
BUTANAL, 3-Methyl-
BENZ ALDEHYDE, 3-Hydroxy-4-

raethoxy-
FORMALDEHYDE

Jasminaldehyde

HEPTANAL, 2-(Phenylmethylene)-

Ketene

Kethoxal

a-Ketopropionaldehyde

2-Ketoproplonaldehyde

ETHENONE

BUTANAL, 3-Ethoxy-2-oxo-
PROPANAL, 2-Oxo-
PROPANAL, 2-Oxo-

Lauraldehyde

n-Laur aldehyde

Laurie aldehyde

Laurine

Leaf aldehyde

Lilial

Lilyal

Lilyl
Lioxin

Lyral
Lysoform

DECANAL, DO-
DECANAL, DO-
DECANAL

OCTANAL

Do-

7-Hyd roxy-3 , 7-dime thyl-

HEXENAL, 2-

PROPANAL, 4-( 1 , 1-Diinethylethyl)-

a-methylbenzene-
PROPANAL, 4-(l,l-Dimethylethyl)-

a-methylbenzene-
OCTANAL, 7-Hydroxy-3,7-dimethyl-
BENZ ALDEHYDE, 4-Hydroxy-3-

methoxy-

3-CYCLOHEXEHE-l-CARBOXALDEHYDE ,
4-( 4-Hydroxy-4-methylpentyl)-
FORMALDEHYDE

Malonaldehyde

Malondi aldehyde

Malonic di aldehyde

Malonyldialdehyde

Metaformaldehyde

Methacrolein

2-Methacrolein

Methacrylaldehyde

Methacrylic aldehyde

Met ban al

Methional

ni-Methoxybenzaldehyde

-Methoxybenzaldehyde

^-Methoxybenzaldehyde

PROPANEDTAL

PROPANEDIAL

PROPANEDIAL

PROPANEDIAL

FORMALDEHYDE , 1,3, 5-Tr ioxane

2 -PRO PENAL, 2-Methyl-

2-PROPENAL, 2-Methyl-

2- PRO PENAL, 2-Methyl-

2-PROPENAL, 2-Methyl-

FORMALDEHYDE

PROP ANAL, 3- (Methyl thio) -

BE NZ ALDEHYDE, 3-Methoxy-

BENZALDEHYDE , 2-Methoxy-

BENZALDEHYDE, 4-Methoxy-

298

2-Methoxybenzenecarboxaldehyde
jD-Me t boxy c innamal deh yd e
2-Methoxycinnamaldehyde
jD-Methoxycinnamic aldehyde
2-Methoxy-4-formylphenol

3 -Me t hoxy-2-hydr oxybenz aldehyde
3-Methoxy-4-hydroxybenzaldehyde
3-Methoxysalicylaldehyde

Me thylacet aldehyde
a-Methylacrolein
3-Methylacrolein
2-Methylacrolein
Me thy lac r yl aldehyde
Methyl aldehyde
in-Methylbenzaldehyde
o>-Methylbenzaldehyde
jv-Methylbenz aldehyde
a-Me t hy 1 but anal
3-Methyl but anal
2 -Me thylbut anal-4
E-2-Methyl-2-butenal
trans-2-Methyl-2-butenal
g-Methyl-p-(tert-butyl)-
hydrocinammaldehyde
a-Methylbutyr aldehyde
2-Methylbutyr aldehyde
3-Methyl but yr aldehyde
a-Me thyl butyric aldehyde
2-Methylbutyric aldehyde
a-Methylcinnamaldehyde
a-Methylcinnamic aldehyde
2-Methylcrotonaldehyde
3,4-(Methylenedioxy)benzaldehyde

Methylene oxide
Methylethylacetaldehyde
Methylf o rmaldehyde
2-Methyl-3-formylindole

Methylglyoxal

j>-Me thy Ihydratr opal dehyde

j>-Methylhydratropicaldehyde
2-Methylindole-3-carboxaldehyde

l-Methyl-4-isohexylcyclohexane-l-
carboxaldehyde

BE NZ ALDEHYDE, 2-Methoxy-
2 -PRO PENAL, 3-(2-Methoxyphenyl)-
2-PROPENAL, 3-(2-Methoxyphenyl)-
2-PROPEMAL, 3-(2-Methoxyphenyl)-
BENZALDEHYDE, 4-Hydroxy-3-

methoxy-
BENZALDEHYDE, 2-hydroxy-3-

methoxy-
BENZALDEHYDE, 4-Hydroxy-3-

inethoxy-
BENZ ALDEHYDE, 2-Hydroxy-3-

methoxy-
PROPANAL

2-PROPENAL, 2-Methyl-
2-BUTENAL

2-PROPENAL, 2-Methyl-
2-PROPENAL, 2-Methyl-
FORMALDEHYDE
BENZALDEHYDE, 3-Methyl-
BENZALDEHYDE, 2-Methyl-
BENZALDEHYDE , 4-Methyl-
BUTANAL (djL), 2-Methyl-
BUTANAL, 3-Methyl-
BUTANAL, 3 -Me thyl -
2-BUTENAL (E), 2-Methyl-
2-BUTENAL (E), 2-Methyl-
PROPANAL, 4-(l,l-Dimethylethyl)-

a-methylbenzene-
BUTANAL (dJ), 2-Methyl-
BUTANAL (dl), 2-Methyl-
BUTANAL, 3 -Me thy 1-
BUTANAL (dl), 2-Methyl-
BUTANAL (dl), 2-Methyl-
2-PROPENAL, 2-Methyl-3-phenyl-
2-PRO PENAL, 2-Methyl-3-phenyl-
2-BUTENAL (E), 2-Methyl-
1 ,3-BENZODIOXOLE-5-CARBOX-

ALDEHYDE
FORMALDEHYDE
BUTANAL (dl), 2-Methyl-
ACETALDEHYDE
INDOLE-3-CARBOXALDEHYDE, 2-

Methyl-lH-
PROPANAL, 2-Oxo-
ACETALDEHYDE , a , 4-Dimethyl-

benzene-
ACETALDEHYDE, a , 4-Dimethyl-

benzene-
INDOLE-3-CARBOXALDEHYDE, 2-

Methyl-lH-
BENZALDEHYDE, l-Methyl-4-iso-

hexylhexahydro-

299

a-Methyl-p-isopropylhydro-

cinnamaldehyde
2-Methyl-3-(-isopropylphenyi;

propionaldehyde

B-(Methylmercapto)propionaldehyde
3-(Methyliuercap to) propionaldehyde
l-Methyl-4(4-methylpentyl)cyclo-

hexane- 1-carboxaldehyde
Methylnonylacetaldehyde
Methyl-n-nonyl ace t aldehyde
Methyl nonyl acetic aldehyde
a-Methylpentanal
jv-Methylphenylacetaldehyde
( 4-Methylphenyl)acetaldehyde
2-Metnyl-3-phenylacrolein
2-Methyl-3-phenylacrylaldehyde
2-(j)-Me thy Iphenyl) propionaldehyde

2-Methylpropenal

a-Methylpropionaldehyde

2-Methylpropionaldehyde

3-(Methylthio)propionaldehyde

3-Methylthiopropionaldehyde

ot-Methyl-a-toluic aldehyde

2-Methyl-l-undecanal

2-Methylvaleraldehyde

Methylvanillin

Morbicid

Muguet synthetic

Muguettine

Myristaldehyde

Myristylaldehyde

PROPANAL , a-Methyl-4-( 1 -methyl-
ethyl Jbenzene-
PROPAWAL, a-Methyl-4-(l-methyl-

ethyl)benzene-
PROPANAL, 3-(Methylthio)-
PROPANAL, 3-(Methylthio)-
BENZALDEHYDE, l-Methyl-4-iso-

hexylhexahydro-
UNDECANAL, 2-Methyl-
UNDECANAL, 2-Methyl-
UNDECANAL, 2-Methyl-
PENTANAL, 2-Methyl-
ACETALDEHYDE , 4-Methylbenzene-
ACETALDEHYDE, 4-Methylbenzene-
2-PROPENAL, 2-Methyl-3-phenyl-
2-PROPENAL, 2-Methyl-3-phenyl-
ACETALUEHYDE, a ,4-Dimethyl-

benzene-

2-PROPENAL, 2-Methyl
PROPANAL, 2-Methyl-
PROPANAL, 2-Methyl-
PROPANAL, 3-(Methylthio)-
PROPANAL, 3-(Methylthio)-
ACETALDEHYDE, a-Methylbenzene-
UNDECANAL, 2-Methyl-
PENTANAL, 2-Methyl-
BENZALDEHYDE, 3,4-Dimethoxy-
FORMALDEHYDE

OCTANAL, 7-Hydroxy-3,7-dimethyl-
OCTANAL , 7-Hydroxy-3 , 7-dime thyl-
DECANAL, Tetra-
DE CANAL, Tetra-

3-Naphthol-l-aldehyde
2-Naphthol-l-carboxaldehyde

Neopentanal
^-Nlcotinaldehyde
_m-Nitrobenzaldehyde
Nonaldehyde
n-Nonaldehyde
Nonanoic aldehyde
n-Nonylaldehyde
Nonylic aldehyde
NSC 8819

2-iiydroxy-l-NAPHTHALENECARBOX-

ALDEHYDE
2-Hydroxy- 1-NAPHTHALENECARBOX-

ALDEHYDE

PROPANAL, 2,2-Diraethyl-
2-P YR1D INECARBOXALDEHYDE
BENZ ALDEHYDE, 3-Nitro-
NONANAL
NONANAL
NONAI'JAL
NONANAL
NONANAL
2-PROPENAL

300

Obepin

Octaldehyde

n-Oct aldehyde

n-Octanal

Octanaldehyde

Octanoic aldehyde

jn-Octylal

Octylaldehyde

Oenanthal

Oenanthaldehyde

Oenanthic aldehyde

Oenanthol

Oenanthole

Oxal

Oxalaldehyde

Ox orae thane

jy-Oxybenzaldehyde

Oxymethylene

BENZ ALDEHYDE, 4-Methoxy-
OCTANAL
OCTANAL
OCTANAL
OCTANAL
OCTANAL
OCTANAL
OCTANAL
n-HEPTANAL
_n-HEPTANAL
n-HEPTANAL
n-HEPTANAL
n-HEPTANAL
ETHANEDIAL
ETHANEDIAL
FORMALDEHYDE

BENZ ALDEHYDE , 4-Hyd roxy-
FORMALDEHYDE

Paraform

Par aldehyde

Pelargonaldehyde

Pelargonic aldehyde

1 , 3-Pentadiene-l-carboxaldehyde

ii-Pentanal

1 , 5-Pentanedione

a-Pent ylcinnaraalde hyde

Phenylacetaldehyde

Phenylacetic aldehyde

3-Phenylacrolein

3-Phenylacrolein

Phenylethanal

Phenylf o rmaldehyde

Phenylme thanal

l-Phenyl-l-octene-2-carboxaldehyde

2-Phenylpropanal

3 -Phe ny 1 pr opanal

3-Phenyl-l-propanal

3-Phenylpropenal

QKPhenylpropionaldehyde

3-Phenylpropionaldehyde

2-Phenylpropionaldehyde

3-Phenylpropionaldehyde

3-Phenylpropyl aldehyde

Phixia

m-Phthalaldehyde
-Phthal aldehyde
Picolinal
Picolinaldehyde

FORMALDEHYDE, Para-

ACETALDEHYDE , Paraldehyde

NONANAL

NONANAL

2,4-HEXADIENAL

PhNTANAL

1,5-PENTANEDIAL

HEPTANAL, 2-(Phenylmethylene.)-

ACETALDEHYDE, Benzene

ACETALDEHYDE, Benzene

2-PROPENAL, 3-Phenyl-

L -PRO PENAL, 3-Phenyl-

ACETALDEHYDE, Benzene

BENZ ALDEHYDE

BENZ ALDEHYDE

OCTANAL, 2-(Phenylmethylene)-

ACETALDEHYDE, a-Methylbenzene-

PROPANAL, Benzene-

PROPANAL, Benzene-

2-PROPENAL, 3-Phenyl-

ACETALDEHYDE , a-Methylbenzene-

PROPANAL, Benzene-

ACETALDEHYDE , a-Methylbenzene-

PROPANAL, Benzene-

PROPANAL, Benzene-

OCTANAL, 7-Hydroxy-3,7-

dimethyl-

BENZENEDICARBOXALDEHYDE, 1,3-
BENZENEDICARBOXALDEHYDE, 1,4-
2 -PYRIDINECARBOXALDEHYDE
2-PYRIDTNECARBOXALDEHYDE

301

2-Picolinaldehyde
2-Picolinealdehyde
PIcolinic aldehyde
Piperonal

Piperonaldehyde
Piperonylaldehyde

Pivalaldehyde

Pivalic aldehyde

Propaldehyde

1 , 3-Propanedialdehyde

1 , 3-Propanedione

Propenal

Prop-2-en-l-al

2-Propen-l-one

Propional

Propionaldehyde

Propionic aldehyde

Propylaldehyde

Propylic aldehyde

Protocatechualdehyde dimethyl ether

Protocatechuic aldehyde dimethyl

ether
Protocatechuic aldehyde ethyl ether

Protocatechuic aldehyde methylene

ether

2-Pyridaldehyde
Pyr id ine-2-al dehyde
2-Pyridylcarboxaldehyde
Pyromucic aldehyde
Pyroracemic aldehyde
Pyruval dehyde
Pyruvic aldehyde

2-PYRIDINECARBOXALDEHYDE
2-PYRIDINECARBOXALDEHYDE
2-PYRIDINECARBOXALDEHYDE
1 , 3-BENZODIOXOLE-5-CARBOX-

ALDEHYDE
1 , 3-BENZODIOXOLE-5-CARBOX-

AL DEHYDE
1 , 3-BENZODIOXOLE-5-CARBOX-

ALDEHYDE

PROPANAL, 2,2-Oimethyl-
PROPANAL, 2,2-Diraethyl-
PROPANAL
PROFANED IAL
PROPANEDIAL
2-PROPENAL
2 -PRO PENAL
2-PROPENAL
PROPANAL
PROPANAL
PROPANAL
PROPANAL
PROPANAL

BENZALDEHYDE, 3,4-Diinethoxy-
BENZALDEHYDE, 3,4-Dimethoxy-

BENZALDEHYDE, 3-Ethoxy-4-

hydroxy-
1 , 3-BENZODIOXOLE-5-CARBOX-

ALDEHYDE

2-PYRIDINECARBOXALDEHYDE
2-P YR I D T.NECARBOXALDE HYDE
2-PYRIDINECARBOXALDEHYDE
2-FURANC ARBOXALDE HYDE
PROPANAL, 2-Oxo-
PROPANAL, 2-Oxo-
PROPANAL, 2-Oxo-

Quantrovanil

See BENZALDEHYDE, 3-Ethoxy-4-
hydroxy-

d-Rhodinal

CITRONELLAL (d isomer)

Salicylal
Salicylal dehyde
Salicylic aldehyde
Sesqulsulfate

BENZALDEHYDE, 2-Hydroxy-
BE NZ ALDEHYDE , 2-Hydroxy-
BENZALDEHYDE, 2-Hydroxy-
STREPTOMYCIN sulfate

302

Sinapaldehyde

Sinapic aldehyde

Sinapyl

Sodium _o-benzaldehyde sulfonate

Sodium benzaldehyde-2-sulfonate

Sodium jD-forraylbenzenesulfonate

Sodium 2-formylbenzenesulfonate

Sonacide

Sorbaldehyde

Sorbic aldehyde

Streptobrettin

Streptomycin A

Streptorex

_p_-Sulfobenzaldehyde

2-Sulfobenzaldehyde
2-Sulfobenzaldehyde sodium salt

Superlysoform
Syr ing aldehyde

Syringic aldehyde
Syringylaldehyde

Terephthal aldehyde

Terephthalic aldehyde

Tgtradecyl aldehyde

A -Tetrahydrobenzaldehyde

1, 2,3,6-Tetrahydrobenzaldehyde

Tiglaldehyde

Tig lie acid aldehyde

Tiglic aldehyde

m-Tolualdehyde

_p_-Tolualdehyde

jg-To lual dehyd e

a-Tolualdehyde

2-Tolualdehyde

4 -Tolualdehyde

^-Toluic aldehyde

a-Toluic aldehyde

-To luyl al dehyd e

-Toluyl aldehyde

2-PROPENAL, 3-(4-liydroxy-3,5-

d ime thoxypheny 1 )-
2-PROPENAL, 3-(4-Hydroxy-3,5-

diraethoxyphenyl)-
2-PROPENAL, 3-(4-Hydroxy-3,5-

dirae thoxypheny 1 ) -
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid sodium salt
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid sodium salt
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid sodium salt
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid sodium salt
1,5 -PENT ANE DIAL
2,4-HEXADIENAL
2,4-HEXADIEHAL
STREPTOMYCIN sulfate
STREPTOMYCIN
STREPTOMYCIN sulfate
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid
BENZALDEHYDE, 2-Forraylbenzene-

sulfonic acid
BENZALDEHYDE, 2-Formylbenzene-

sulfonic acid sodium salt
FORMALDEHYDE
BENZALDEHYDE, 4-Hydroxy-3 , 5-

dimethoxy-
BENZALDEHYDE, 4-Hydroxy-3, 5-

dimethoxy-
BENZALDEHYDE , 4-Hydroxy-3 , 5-

dimethoxy-

BENZENEDICARBOXALDEHYDE, 1,4-
BENZENEDICARBOXALDEHYDE, 1,4-
DECANAL, Tetra-

3-CYCLOHEXENE-l-CMBOXALDEHYDE
3-CYCLOHEXENE-l-CARBOXALDEHYDE
2-BUTENAL (E), 2-Methyl-
2-BUTENAL (E), 2-Methyl-
2-BUTENAL (E), 2-Methyl-
BENZ ALDE HYDE , 3-Me thyl-
BENZALDEHYDE, 2-Methyl-
BENZ ALDEHYDE , 4-Methyl-
ACETALDEHYDE, Benzene
BEl'IZ ALDE HYDE, 2-Methyl-
BENZ ALDEHYDE, 4-Methyl-
3ENZ ALDEHYDE, 2-Methyl-
ACETALDEHYDE, Benzene
B ENZ ALDE HYDE , 2-Me thyl -
BENZALDEHYDE, 4 -Me thyl-

303

-Tolylacetaldehyde

o-Tolylaldehyde

-Tolylaldehyde

Trichloroethanal

Triformol

3,4, 5-Tr imethoxycinnamaldehyde

Trimethylacetaldehyde

1 , 3, 3-Trimethyl-2-(formyl-

methylene)indolene
2,4,6-Tnmethyl-l,3,5-trioxane
Trioxan
Trioxane
^-Tr ioxane
sym-Trioxane
Trioxin

T r i oxyme t hy 1 e ne
Tylan
Tylon
Tylosin

ACETALDEHYDE, 4 -Methyl benzene-
BENZALDEHYDE, 2-Methyl-
BENZALDEHYDE, <f-Methyl-
ACETALDEHYDE, Trichloro-
FORMALDEHYDE, 1 , 3 ,5-Trioxane
2-PROPENAL, 3-(3,4,5-Tri-

methoxyphenyl)-
PROPANAL, 2,2-Dimethyl-
ACETALDEHYDE, 1,3,3-trimethyl-

A-(2,a)Indollne-
ACETALDEHYDE, Paraldehyde
FORMALDEHYDE, 1 ,3,5-Trioxane
FORMALDEHYDE , 1,3, 5-Tnoxane
FORMALDEHYDE, 1,3, 5-Tr ioxane
FORMALDEHYDE, 1 ,3,5-Trioxane
FORMALDEHYDE, 1,3, 5-Tr ioxane
FORMALDEHYDE, 1 ,3,5-Trioxane
STREPTOMYCIN, Tylosin
STREPTOMYCIN, Tylosin
STREPTOMYCIN, Tylosin

ja-Unde canal
Undecenoic aldehyde
Undecyl aldehyde
9-Undecylene aldehyde
10-Undecylene aldehyde
Undecylenic aldehyde
n-Undecylic aldehyde

UNDE CANAL
UNDECENAL, 9-
UNDE CANAL
UNDECENAL, 9-
UNDECENAL, 10-
UNDECENAL, 10-
UNDE CANAL

Valeral
Valeraldehyde
n-Valeraldehyde
Valerianic aldehyde
Valeric acid aldehyde
Valeric aldehyde
Valerylaldehyde
Vanillal

Vanillic aldehyde

Vanillin

_o-Vanillin

Vanillin ethyl ether

Vanillin methyl ether

PENTANAL
PENTANAL
PENTANAL
PENTANAL
PENTANAL
PENTANAL
PENTANAL
BENZALDEHYDE, 3-Ethoxy-4-

hydroxy-
BENZ ALDEHYDE, 4-Hydroxy-3-

methoxy-
BENZ ALDEHYDE, 4-Hydroxy-3-

methoxy-
BENZALDEHYDE, 2-Hydroxy-3-

methoxy-
BENZ ALDEHYDE, 4-Ethoxy-3-

methoxy-
BENZALDEHYDE, 3,4-Dimethoxy-

304

Vanirom BE NZ ALDEHYDE, 3-Ethoxy-4-

hydroxy-

Veratral BENZALDEHYDE, 3,4-Dimethoxy-

Veratraldehyde BE NZ ALDEHYDE, 3,4-Dimethoxy-

Veratric aldehyde BENZALDEHYDE, 3,4-Dimethoxy-

Veratryl aldehyde BENZALDEHYDE, 3,4-Dimethoxy-

Vetstrep STREPTOMYCIN sulfate

C B

O I N^

H

CO CO

rH M rJCC

0) O *-> ^

> 4-> M S

P o 6 a

o ca a.

CJ ft, -H -^

CM

3D

s

o

X c-l

C

CA H

X)

I 3

<U rH O
> 0) CO

CJ
O

H

QJ
C/D

m
o

co
cu
H

4-1
JH
QJ
ft

S

t

cu

6

O ft
Pn o

a c.
o 3
^* o

I 1 I i
PH PH

H -H
4-1 rH

CJ
33 o

M CO 00

& CO EC

CU 01

ca n 1-1 a

rH 00

CM

r-l O

CJ

01
X)

I m . o

00

o

m

o

7

CM

4J ^H

M H II

a CO M

C i-l

cd 0) co

> a ^

PM

4J -H O B

U CO X 00

fl iH

CU 01 O M

O r-l 4-* O

00 "-.

r>. oo

o

CM o

r*^ *^

CM ^^

O O

. CM

oo si-

o -^

o o

CM

4s

W

H

m
o

CO
CM

co
sf

1 O

i

I

0)

(L) W

0)

CO

nJ

I

QJ

vO

01

C

C CD CJ

C 01

rH
1

O

a
co

ALDEHYDE
3 CHO

nzene
acetaldehydl
C 6 H 5 CH 2 CHO

rH
>,

X

4J

I'
H

a
-*

benzene-
acetaldehydi

C 10 H 12

7-DIraethyl-

octenyloxy-
acetaldehyd

CM

CM

i

Fonnylbenze
acetic acid

en
O

3?
CTi
CJ

Methylbenze
acetaldehyd
C 6 H 5 CH(CH 3 )

-Methylbenze
acetaldehyd
C 9 H 1Q

(U

H X

0)

M

**

i

i

i

e

W CJ

a

o

en

B

a

"^*

(0

CJ

305

P. 00

6

CO CO

h h tJco

<u o *./-

> 4- op e

c y g e

o co c

O fc p i v-

CM

en

00

o

o

J3 CM

3 33

TH

O C

CO H

XT XI
00 3

JC X>
OQ 3

H O
CO CO

J5 X5
00 3

X)

3

O
CO

XJ

CO
Cfl

O fe,
(X, o

oo oo
c c

H H
tJ i-H

O U

cq o

in r-
I en

CM
l

m
-M

CO 00

ro n: x

01 o

t-i jj S

0, 3 6

o
m CM

a CO H

C -H

ca <u eo

> Q s_^

4-> -H O
r-l 4J cvT^

co cd K oo

CM
O "->

O

O in

CM O
. CM

CN
CM

o

CM

CM
CM

13
0)

a
rt

H

o

bH

a

(0
CU

e
cd

55

O
O

DEHYDE

e

s -

cu

g,
5 -g

XT CU T3

C f-J

<U crj

N U

C CU

0) CJ

XJ cd cj
*

Q)

d

xTo
cu -^
d

n

S -A

^

td
cu

1

7 i>

H c:

<u

&i -H Q)

TJ

X! rH T3

>>

W >,

Xi

a> T3 x:

1 QJ
T)

E c cu o

H -H T3 3

M ~| K

M 1 rH u"

CO CJ

f-'^Cd -

r-l 4J CO

1 8 W 5G

x: cu H

CO " CU f

U

~cM O "

H cj

CO N-X cd O

j-i

M

E-

F-H

g

So

3

J m

< X

M vO

K CJ
W
OQ

306

30

en

OO
vO

XI

3

XI
3

XI
D

r-l
O
CO
C

X! Xi
M D

r-l O
C/) CO

>> i

m

_f

I

O

CM

CM
00 -s.

O r-H
CM

CM

oo

csi

O

m

CM

fi

CM

/~\ Ol

o -a

C rSO

i-t X! J3

c| 13 O

rH rH CM

^1 Cd rH

4-1
01
O

C

o -o
a >%

rC O

- g

(U r-
-Q O

01

I T3
O >i

x;

01 CM O 01 O

a CM

X: rH rH

cd u
H N <r

Q C 3C

1 01 r
O XI O

*

Cd rH

N X

. . C -H

Q 0) -H

v_x Xi U

01

I 0)

>> -o

X >^

XT
XT QJ
4J -O

01 rH

5 2
?

m xi

A

CM

U
CM

O*

CO
33
O

I 01

>> n

xi

QJ U
T3 CM
rH x^*

Cd O

N m
oi o

X) v^

I OJ
H T>

x: cd

U N

ai c

01

H XI O

a >-> -a-

ai
ts

0)

cd

3

o

X> CM

H
sf

307

a oo

C

00 -^ ON -O

in o

o

O rH N_/

J3 r- r-

00 IT)

m

m

CO CO

-" >-l ,-JCd

01 O ->. *-

> 4J 00 B

c u S a

O cd Q<

CJ &H -< ^

* CO CN C*">

00

-

rH -M

o

'N

o

'M

.fi CM

HO) H (U
U H 4-1 H

'S'rH

r^ OJ

i-H 01
4J H

... ^ *Tn ^

X- ^

J3 >

r JQ

^j

H J 2l

00 3

00 3

00 3

C
C/> iH

HO HO 1 |
CO CO CO W 1 |

^ ^
H
1 CA CO

H H
H
tt) CO

rl H

rH O

C/3 CO

ca C

ed iH

rH tn
tti PU

i ! !

I 2

1 rH

1
1

1

*** *

4-J -|J

Ot PM

M 60

CO

rT"

CO

M C

"**S. "w H

1

0)

H tH

oo >n -H

B

4-1 rH

\ OH

H

rH iH

fl) O O
Js 03

1 1 jQ

j^- <t p 1 I

1 f^ 3\ ft,

O -*

-i 3

'n i i

1 | -H ^

-t CM

1

h co 00

o to .3: /-N

fti 01 01 U

Jon

rH

vO

rH 3

CM r-x

cd f-i n s

! ! ' '

rn ON

^

-H rH

f 1 " 3 v--

iiii

! ^^

O

rH O

t

CM

CM

i-H

4J rH

H -H ||
&CO t-l
C H

> Q s->

iii:

.
l -4-

1
1

2

OJ

/-s

>-, > rH

s~\

CJ

w i-l O

U

o

H 4J CNT^

^

*^

w cd x to

p*^ <f

CT -^

C iH

vO * s ^

CN O

0) 0) O rW
O rJ 4J O

i i i i

i "*

. CM

1 rH x-

1

"H

00 i-H IT) ON
^ CM CM -H

r-. co

o

i l

rn

rH

' 1 CM -H

00 CM
O CM

CM rH

CM

CM

r- 1

CM

CM

i-H

TJ

CU

D <

"^

H ^ 1 1 S

S 1 o o SSo
r9 cdrrt-, ^ <uo33oj-a

1 - 11 SI -f*^ su

E S t-^ ? n .^^ S "

-r | 1 ts^ ^-So^ r g^ JS^ M

I ^ ^ S*"I3 O frrHjNrHiW/^ i-HC^J
"^ T3 S OM3S5jT < b lH:i! >.OO
C J -Cria^ 32^-. 03CO S4Hv_-

Cd a 3 "SS* ^coficoo ErHST

I 1 ?-^ ?-cT ^^ g -

< I " * -* N

2-Fonnylbenzene-
sulfonic acid
sodium salt
C 7 H 5 Na0 4 S

2-Hydroxybenzaldehyde
C & H 4 OHGHO

3-Hydroxybenzaldehyde
C 7 H 6 2

4 -Hy d roxy b e nz al dehyde
C 7 H 6 2

308

-? 1

-H

O

CO .0 1

)

30

( -H 1

(

0)

s*, >>

>-.

iH

-H CU rH 01

^ Oi

X

4-1 rH 4-1 -!

4J i 1

3
,_4

00 3 OC 3

oO 3

H iH i-l i 1

H ^1

co

-HO i-H O 1

^H O

c

CO ID C/2 CD 1

C/3 CD

t

sf

1 1 1

1

-a-

1 1 1

1

CM

l-i

CO P .O

o-

O"\ O ^^ >>O

***^

"x^

*^

i jj in -M

co

00

CS

**^ 1 *^" 1

00

CO

I

co tN <r I m

1 ""*

1

ro

1 O\ H -3- -O I

1

r*^

^

"I 1 s ' <J" "\1 1

OO CM

CO

'M

x-\

00

x^ x^.

X-N

r~ O

m

1 1

O P~-

CM

XX

1 1

x-< v-X

N_X

1 -H 1

i m

30

-H

CM

1 1 1

1

1 1 1

m

1

u

/-N

O

m

CO

-^.

o

r I

1 1 1

CM

1 1 1

"

-H

~

I 1 1

vO

vO

CN CM

CM

oo m i

in

co

i i i

""

r 1

0)

CU

-o l i

1

o

> O

^

XX X

X i

X

^ J 5

U

cu

t:

T3 iH 4J 4-1

4-f "T*

H

O

I co QJ cu cu a)
m N g -a 6 -a

C 1 >* 1 >-.

CO CU CO X * X

0) 01 ^O

6 TJ ;j

H
111

33
co

IX 1 CU 1 CU

i "aj o

X

33

>i >> -^" >^ T3 >> "O
XXO XrHCO Xi-{
OOO OcflO OC6
l-i X I UNOO ^N

*"O -^ *T^ *^J ^ *T] ^Q j

>~iCU^ S^CUSO >><U
X60 =3X0 33X

X "H X~N

CO
l-i N CO

a c 33
> cu u

33 X ''^

Methoxy

O

vO
O

1 1 1

1

i

~* <N fo

<!

CM

-< O

CM

vO
CO

CU
T)

X
cu

r-H O

id 33

N U

C s~*

QJ CO

>> CJ

X O

O - '

X j*

(U vO

S O
I

O cs|

CU
T3
^
CO
N
C
CU

^ co

H CU Q)

4J -H X

00 3 X

H rH 4J

-( O H

C/> CO ?

vO
CO

O CT

o

CM

0)

I

01
T3

00
-U 33
CU 00

309

H4

O. 00

E

C
O
1-1

09 U

(-1 U JfO

01 O -v. --N

> U 30

c u E a

o co a.

u tx, - v^

o
eg

CM

oo

CM
oo

o
ro

en
m
m

Ol

sa f

iH
O B

rH 01
AJ rH

x: -Q

00 3
H -H
-I O
00 CO

H 0)
U rH
JS XI

oo 3

H rH
H O
CO (0

x: xi

60 3

rH <U

U rH

X! XI
00 3

H rH

H O

CO CO

x:
ao

rH O
CO CO

>-,

rH tt)
U -H

rH O
00 CO

0)

rH
JO

o

CO

x; w

u c

CO -rt

H O En

[IH P-. O

PH PH

M (0 00

&n > 33 <<4

01 01 o

C8 r-l ^ S O

> O, 3 i v-/

7

* m
I co

I CM

30 O
-^.^4-1
O CM

CT> I -H

I m r>.
o\ *$ r*.

30 CM '

!->.
<=f

CM

CO
fM

CD

cr>
I

o
eN

aU)
c

CM

LT|

CO
st

" 01
>> >

H 4J

o a

CNT^.
cd 33 60

U
Ch o

oo ^r

o

in
m

C

01 0) O

a M

CM O
CM

O o

00 O

CN

O ^

O u

S 3

T3
QJ

3

d

w

r-l

o

CM

01

I

CM

to

rH

1

l

id

r-l

CO

3
B
-i

2
a>

N

01

O

Ex

JH

X

Xt
H

Xt
r^

a

c

C8

3

X

x; ao

w S
Q) 00

>

W
01

u

g

f

^

B

w
aa

-o

e

^ I

fM I

1*

35

vD
H CJ
> CO E

f? -P u

>> CM

X! x^
0) CO

T3 M

" H U
v-" cd ^/

>*

CO

o

1 I
CM

01

,1

H 01

>*. -a

X H

01 Q

X! N

C

CO Q)

V -

1 o

"? ^
i -a <

53 =
f^,

si-
co

*

I

o

310

CT>
CM

4J -H
JSJ3

-H O

cn

X-Q
M 3

iH O

en a

00 3

3

S'ex
a 3
o o

0)

ex
o

m
m

as o

i a

cu co

a a)

co

m o
TO ex

.

OCO

ICN

m
o

I
m

oum

O ^-N

. o

O CM
CO v-/

m
en

U
O o

ooo

. -N

O ^-^

3 o

os st - ^

w in oo o

CM -CM

O *-* O v-*

en

w

4J O

T3 O

s^'sc

o

OJ O

55

w a

at

as

is"

311

C E

O i v-

W CO

l-i Jeg
O

QJ

> w

C U

eg

U fa

00 G
S a
a

CN

CM

01

C
CO iH

-

00 3

J3

3

O
CO

C
M

-Q
>, 3

0) O

> W

CA
0)
GO
O

a
I

CJ

OJ

a

CO C
Cd -rl
rH O fa

O, OH

g?g>

o u

M o

*-. CTi

in o

I CM
00

o \o

-*

.

o

m

a co
0) OJ

..

cfl M (-1 S '
> OH 3 S '

^N O

m O o m

rH O 00

o
o

d --N
o o

*-t CM

U -H ||
O CO M

a c -H
eg a) eg

> a ^,

- 0)

5-i > H

u -H O S

H JJ CM<

W eg I 00
B H

<U O to

QJ

a

rC OJ

CM

--<

CM

OO

m

CM

.a-

^

H

>>, 0)

ia

2|g
1 D 03 CM

-1 rJ [I] K

CJ S \L(

:LOHEXENE

)EHYDE

^o

X ro eg
p 1 X CM

>-" >^ O O

T3 H ,0 CM
>, >% to CM
M 4J eg -H
1 C co
* (U 1 -H

CJ
00
/~\
CM

^5

S ^^

H >* _] ^

JJ j "7?

Y- a-H cj

Z CO

ycj < u

V<C CJ

1

^ 33

i

^^

^

CJ

-*

en

U

i

W O
g U
O T

z CM
w sfl
go

312

CM

r^

^

r>>

co

en

"

H

! -

CO

-*

30

m

CO

^

m

CM

i r*

m

i

rH
CM

m

m
m

m

00

j CM

CM

CM

-H

-H

eg

CM

,

01

(1J

rH
01 O CU

01 CJ

rH

01

rH

rO

r-l QJ

4_)

3

JD

A C 5
3 -H >% 3

rH l-l rH

J3 O
3 CM
,__!

00
!_)

3
,_j

rH

8

jC ja
00 3
H rH

ft

O QJ O
W 4J > W

C/5 CO

rH
C/3

O
CO

c

1
1

1

H
C/3 CO

C

rH
CJ

rH
U

c

QJ ^""N

Ol

CM

r-.
m

X CO CX Q.
if) i O 3
^i rH v^x y

=3 "a

* 3

rH

1

1

-* O-

S 3

1

P.

O\ v-'

a

3

30

---. Cfl I-H

^_^

rH

/-N cu en jo

M

rJ

rH

T3 W in 3 4-1

m

M

r-l

HO rv. 03 CO

i

O

Sf O

rH 0. V-

^*^

^

rH

4J

p* 4J

CM -H

o g m co

CO O . rJ CD

>_/ O ->. < l-i E

in cu * ~H o in

CO rH

CO vO

CO
CO

X)
CM

O I--

OO 1

O
CM

***>

I

V -*

^> co m
( ^ P--

vO 30

ir> CM

1 1 v '

CM a VO rH 4J rH

1 rH

1

-H

I -H * '

1 r- 1

X

x-s
O

tn

^^

1

CM

o

^^

CM

o

1 1
1 1

>n

vD

CO

i

1

1

1

O

i l

m

o

1 1

CO

.

1

1

1

*

i

! i

co

CO

1

1

1

cn

CJ

u"

o

CJ

m

G

o

00

O -">

t

m

^^

CM

CTi

m "*x

CJ

O\ <T

en

rH CJ

m j-\

CM

30 CJ

CO

-H O
CO CM

P^ o

rQ ^

00

O

r~ o

en CO

-ft m

m

Cn o
CO

r-H

OO

O ^^

i ~? 2

1 -H ^

CM

CM

^D ^^

o d

CM

CM

i***^ s^.y

d

en

CO

^

vO

CO

X 00

o

rH

CO

CM

i-H

^^

o

s^. O

t

t

*

o

vO

^

CM

O

^o

O

d

CO O

en

<

O

sr

CT*

o

fO

^ ON

-H

CM

rH

rH

O

X

o

|

m

W

/^

X

a

0)

o

QJ

b-t

a

CJ

X

ORMALDEHYDE (gas)
HCHO

Paraformaldehydl
(HCHO) x

1,3,5-Trioxane
C 3 H 6 3

-F URANCARBOXALDEH'
C 5 H 4 2

-HEPTANAL

CJ

m

N

CM

CJ

X
CJ

2-(Phenylmethyle
he pt anal

CJ

*. *

o
-*

X-N

^

cj

v_x
JTO

CJ

, 6-Dimethyl-5-
HEPTENAL

(CH 3 ; 2 c-

CH(CH 2 ) 2 CH(CH 3 )C

, 4-UEXADIENAL
CH 3 CH=CHCH=CHCHO

5

is

w

r

s|

1

(n

CM

a

1

CM

CM

^

313

&

g & 1? => ^

JO CM

fM O

3 -~ sr .= o ^

Ln ^

CO CO

OJ O x-\

> iJ M

c a a a ^ _ _,.

o o. 3? 3 S ^

CM i

I CM

COfa-^ csj _ _ ;*

r* vo

1 -H

ON <j-

1 r-l

0)

1

cu

^n

. o -

.> CH 3

rH

JO

3

>. >N

-H CO rH Q)
4J i I 4J _J

M B

iH

-^ i T i f
,C -Q JS -D

c i i i 2

o
co

60 3 00 3
*rH <H '.-( i^

W-H ! j J e

! 5

HO i-H O

1 1 1

CO CO CO CO

A '

JC 4J

CO C

oj H

Sfi-* j ! j .

1 1

11 i i

1 1

1 1

1 1

\

x-x
4J 4J V-l

/ s

o-i a, 1-1

CO

Q

cu

W) op r-. J- 1

CO

o

H H ^ f~-

n.

U iH | CM

1

H -H _^ ^ s-

1 o

Q) O CJ 1-3-1 , -- CM

! - ! ! 32

\ \ON
1 ON 1 CM -rl
1 1 CM v_x

1 r^ |
1 -H 1

i

h CO oO
Q CO 33 x-\
O. 0) CD CJ

1

* OO

in | r-H

1 -H / N

x^

^ X"^ I 1

M CO ON

r*% ?^*> N^/

> * s 1 - ! j j j

en ON *~\ *~s &\

CM ^ in ON CM -H

v- i i CO
O ^ .
CM CO O

S^'-N
4-1 -H

CO M

a. c -H

id cu n) i i .
>Q- i i ! J

! !

1 1
1 1

" <U s-^

>* > H u

/ s

/^

*' TH O ( o

CJ

^j *-> c\r>- ON st
33 M ^ v^

Sw h "Si
U 4J 0^-1 J {

sf o 00 X-N
vO <J- 00 O
CM -V, CO o
00 CM 00 O
CM .CM
O <^- O v-x

-HO | O x->,

-H si- in o co
CM "^ CM co o
oo o o"> ON m
CM . . _H

v-* "-'

". ^ 2 S

Is s 3 3 s

sr si-

CM CM
CM CM

sf m

CM r-
CM CM

CO CM

CM r^

-< 1 O

i i i

33

CO

1 J

33

1

1 (Q

co

i i

H C

/"N

-c 1 S

=3^

-S UH

CJ

aj

S

" 33 1 i Q 2 ^

1 CM

H

n>H

1 i r? sl 1

CJ cvj jj | 3 JJ

U CM 1 *r4 f~* 1^4 ^J ' *&

^ 33 ,ii 3 \o 3 "- 1 W

10 ^^CM Je"b!.3 : r' -L2 S^^QCM
c ZK "5^^-, 713 21 xaSKo

WO 52^3^P OH3300

K ^ f" ^? o -5SS*

g f - ^cocj- ^^^ -

15 CM ci,

^ ^ M

NONANAL
CH 3 (CH 2 ) 7 CHO

3,7-Dlmethyl-2,6
OCTADIENAL
(CH 3 ) 2 CCH(CH 2 ),

OCTANAL
CH 3 (CH2) 6 CHO

7-Hydroxy-3,7-<
octanal
C 10 H 2(jP2

QO
CO

o
sr
en

ON!

-a-

o

CM

00
CM

<U 0)

00

cu

r-l
JO
H
O

co

H

U '-N
v-x (}.
ST 3 00

m o 's

Ul

/ \

l-l

CO

o

(1) ."-N

4-1

CO -3-

-v. O -H

l-

i ^ a i

"^^.

-o

CM so B

m

i^

~H O

V_ '

0\ | PLj

t "o

"->. vO

o r*. QJ

CT. o

1 -l

-H T3 CJL,

1 -H

1 -H

1 -H V-'^

00 CO

CO

7

r-. O
co O

o in

-H O

o

ro

I u />.

CO 0\ U
u-l U1 o
O> OS m
. fM
O O ^

o \ o

00 O CO
IN .

O v- ' O

u

30 O

IS

. CM

vO

o

* vO

* i

*O i~**^

oo o

o

CM

3

l in

CJ

^s 33

U

/^

<U <>

a

en

5w

3;

OJ M

33

rH U

i-H O

U

*J

CO x. x

>. n

a

C 31

j= ^

-q

cfl U

,-j

M O
CU 31

e o

r-i H "-^
>* "3

a c m

^
O

O *- CM

33 C 33
U 0) U

ma CM

/^ ^ 33
co>sU

<
M X

o u

W CO

z ^

< CM

a) (d -H

U CM

J =3 J2 en

P 33

^= -U 33
OH O vO

Cd O
*^ ^f

< 4J 33
2^ ' OJ U

z C

U v^>

'-'

"^H ^C

<3 cna

0-, 33

1

Ofl CO

E- 33 1

1 U

CM

K u

2; cj CM

m o

ix!

u

M

O

a.

-H

a u

rt CM

a 33
o u

l-i CM

as3

(U CJ

c in

OJ 33

N ^o
e o

CU

oq

315

H
4-1
C
O
O

w

,0
s~*.

cn

a'oo

00 O

C 6.

O i s^

r^ m

H

co co

CU O -v. ^

C> W OO B

ti o B a

Qt O*

o cd ex

-N CO

CJ [L< i-H s-*

-H m

CU (U
_J _J

r^i r i

A 43

O

3 3

-Q 01

H rH

3 33

SO

,_(

CO

C

C C

M iH

M M

^-s

a

i

3

^N

r; jj

O

C

CO C

<u

O H -H

a

H O ^

1 -vT -1

o

Cu P- o

1 \ ^ I

<^x

^-s

4J 4J

Dtl pt|

^-*>

Li

C? P?

en O ->.

H -H

,-H 4J ON

U H

|

H -H

-v. cn CTI m

01 O O

g M o

Icn CTI o in
i s^ I v>

1

^^ cd

Li ca op

m o

a cu cu u

^H V

~. o /^

Cd M M | o

> A4 3 i ^

v^ r~* O
m i CM

*
4J 1

rJ -H U

W M

a. ci -H

5

CB QJ Cd

> a **

|

1 CM

^ H

/-s

O

u -H B

^N a o

H 4J CM"-*

-H U <* st-

co cd A DO

in o ON *""

a H

<r> in f- o

co cu o LI

Q L: *J O

-H CM

v-' O -^

ON CM

CM rH

H

O CM

O JJ

CTI r^.

<

1

(U

d

0)

N

/-\ cu

O <r^ cd

cd

4J H e

1

o

Cu

fl > cd o

6J2 O. 32
1 U O U
>* 0) H D 33

I T rH cd o cxo

rH >, C 00 H CM

j 1 ^| rt cd i^ ^i '"'N

TO

2 X! 4J CX 33 Xi cn

c3

Z 4J cu O cn *J 33

2

$&<?&$

1 1

3

a CM

cd

b

z

s^

o

en

en
-a-

o
en

o

en

en

CM

m

30

en
en

m
en
CM

en

o

si-
en

en

-H

0)

r-H

JQ
>> 3

Ll rH

cu o

> CO

rH fl>

4J H

00 3
H H

rH O
CO CO

-^ en

m m

<Ti |

m

I I CM

1 30 CM 1 st |

I 1 r^

1 1 m I oo i

-a- o in m

I I

I rH OJ 1 -H

1 I

| CM v-> 1 CM ^

sl-

CTi

i i

I.I 1

1 1

1 rH | |

G

in ^

O o

m o

r-l 3"

Sf

sf ^^*

o <t

co o

1 CM

1 CM 1

| rH N-^

1 1 1

30 vD

vO f- -M ON

-H

O O CM rH

* CM

CM vO CO CO

co r^

p^ m o i>

i

CM rH

1

>H
CO

X

C

cd

21

a

/^ 4J C!

o

rH CU QJ

I >, s 5.
m c3 To

^^

cu en Li

rH

cn j: I a

H Cd O
rG fl 33

u cd U

1 P,rH fS 1
>, >, CCJ X CM

X X C sr 1 en

rJ O OOOJO Ll^-vO

?-, OT O O
* O Li U

<J r-J.33 LljSacMtJrHO

M <;O T34JOrH rSr^rH

4J 00 pj \*s

OJ 33 en
S st 33

Q CM ^33 ><.gJLiX 31 fl 33
W O W O 33 G r ~* 1 el) O

Ssf Pi II Trll ! <f^3*- (

v^/ CJ O U

<33 OCM <l-'dCMO v-'D.O

1 1

0^ en oi 33 v-* 1

en CM

O u &i cj <n en

316

o
.0

en

CM

vO

m

c\

-d-
en

CTi
CM
CM

CJ

J3

H
O

.

>, M 3
M H iH
CU ^H O
> CO CO

o ca B

"M O

/\ \_x m

C
CU

o. /-x

o a

v^- 3

m o

I in

1 =0

I ->

4J CO

jl cu

00 CO

^.3 1

m s-/ o

o

r^. m cu

I CM T3

O
CO

T

00
CM I

4.6

u

r>. o
-d-

.
f-

CJ CJ

o r-. o

r^ -^ <JN -sd"

co --. * \

oo o o o

CM CM

O ' i ^-'

CTi

32

CM
CM
CM

93

m

CO

m

-d-

Jt

O
en

gv
&g

B,^

I vO
CM CJ

1

cu
o- o

O US

I CO

CM 3d
I CJ

H ^

>*u

JZ II
iJ CM

cu as
f u

CM

cd

a
cu
a.

g

Q.CJ

CM CJ

1 II

m
3d

fel

o cu
w o

CU 1-1

B ft

^ I

CM

O
CO

4J

m

A

-d-

M

co

*^x

1
CO

P.U

3

CM

H Z

1 1

3

Z -t

O <T*

o

CJ

M O

X CO

z

W M

CJ r-..

B 33

r

H >-i O
3d IS

CTi
CO

O '-i
4J CM
O.CJ

C r~
H 3d
ca m

H w m

E- 3d

01 s-'

o -si-

p3 a a

p i T-H

M CM

H CJ

P J vD
PH < CJ

W ""J

2 cj

J
CO

^

1

t-i

CM

C/3

317

en

B B

a op o

in CT\ ^

C B

O -i "^ r>

r^ <iO \o

H

co in

n M Jaj

01 -*^

> .u M 6
BUBO. sr

en in m

o cd o. <

en <f -<f

CJ tn *H v-^ ,H

-H i 1 H

(U

H

^

jQ

H Q)

3

J3 01 H

4: -a

3 M

M) 3

H CO

H H

O C (3

HOI 1

CO 1-1 H

CO CO 1 1

"m C

d "H in

H O to en

I

tn eu o CM

1

4J 4J

H H

4J H

H H -v.

OJ CJ vt
S m o |

1

T

M CO 00 -1

-H

a co > M /-\ IH
01 CU CJ s^

^

cd rj li B oo

| |

^

- 1 1

U iH 7
W t-i

a B -H

cfl (U ed i

1 1

> Q -^ \

1 1

* $ . -^
>i > H cj
w H g _ o

/-x CJ
U o

I m

CO cd EC 60 CM "^

O st O O CM

C H CO en
01 0) O r-l .CM

O r-l W O O <^

oo in oo oo m

I . CM

O ^/ O O > '

O

en co so

H .

en CM CM

Q O

Sf 90 00

-H

00 vO \O

O

a

CJ

cd

H en O O

S3 g I

cd v-^ r^ TO

r-l

E
5

O J CTi

o a ^ <-,

0) CJ CM rH CM
T3 00 prt co 33
g -N U dCJ
3 CM J ^ cU v-/

cd u > '

Q en

H ad 3 a o a
>% cj z o o> fcj

l> S * I-'CM

I 8 Ig"l B

r2 '

1

C|

ON

OJ

H

TJ

XI

^

3

pC

U

01

TJ

rJ

a

01

a

m

CO

o

c

r-l

o

H

oo

H

H
H
B

rH
H

B

M

c

H

.

C

CO

o

t-J

4J

cd

a.

^

4J

o

0)

CJ

i^

C

0)

o

rQ

CJ

B

3

cd

o

01

JS

u

4J

o

01

4J

rH

CO

U

C

H

0)

3

rH

cr

cd

01

H

CO

3

H

cr

01

^^

CO

S

H

CO

0)

i-H

T3

J3

CJ

01

O

nQ

m

1

CM

O

H

CO

c

B

H C

H

I

OI

r-l rH
4J O

"?,

C

0)

01

O CO

o

C -H

X

CD

O 4J

01

C C

ij 3

3

rJ B

0) 3

W

CJ

H X

B

rH CO

O CO

H -H

j -i^

^H *C

oi B

nH W

^

a w

H

4J

ca

B B

H

I-H

M

cd

r-l

M

& 3

(xO

H CJ

Q

rH o

4J X

CJ

rH m

r-l CO

H

H CM

CO

4-1

S ^^

a M

H

01

CJ

0) r-l

0) iJ

01

d -H

B 0)

0.

^^ fl

B

CO

cd

U

318

CO

a)

!

O

co

1 rH

4J

CO cfl

c

O " 4-)

CU

H rH C I >

50

4-1 O 0) CO 01

cfl

0) C P- > C

01

co ' cfl

M

cfl w a

3 01 - O

ts

TJ 43 TJ >H rJ

l-l

rj | -H CO P.

O

Cfl C| l-l rH
1 CO

4J

cfl

TJ H rH
H Ol O 43 >i

O

O TJ H tJ -3

43

Cfl >, 4J 4J

CO

^: cu cu

rH

U Ol O CO S

H T> (0 OJ -H

4J ^H H C U

aO

cy cfl o) H w

O O. TJ

C
H

CO rH H

M

>> t-l rH

O

m _** rH ^ o

^

O 4J O P. O

cfl

01 C >. CU

rH

Ol CO rH 4J

4H

U X rH bO CO

3 01 3 H
4J TJ 43 4J OJ TJ

CO

O H rH H O CU

d)

CO Vj >, J-l 0) S
M-l TJ f 43 rH H

3

3 >, 4J 4J >, 01
G J! Ol 5s 4J 4J

H
M

rt ^ 1 l-i 3 S3

01

Z cfl CM CU 43 -H

^

if

H

rJ
O

PS

T^

o

5s

c

43

>.

C/3

01 0)
TJ <U TJ
Ss TJ rH

TJ

a

43 X Jfl
01 43 Q
TJ CU M

cti

H TJ

^rH^

CO g.

O CO rH

^ a

iH (3 rH >%

CO o

*J CO tS43

P c

01 J3 43 4J

>s

en

CJ 4J 4J QJ
< W W S

CM
I,

W

3

o

D.

e
o

CJ>

rJ
01

43

Z

o

(-1

CO

01

e

TJ

CO

<U rH

o

01

^3 CQ
n) t>% d

0)

T)

T)

?>

Phenylacetaldehyde
Benzeneacetaldehyde
Hyacinthin
Phenylacetlc aldehyde
a-Tolualdehyde
a-Toluic aldehyde
Phenylethanal

2-Methylhydratropaldehyd<
2-Methylhydratropicaldeh;
2-( p-Methylphenyl) propio

Citronelloxyacetaldehyde
6, 10-Dimethyl-3-oxa-9-un

a -Fonnylphenylacetic aci

Hydratropaldehyde

TL -Phenyl pr opanal
2-Phenylpropionaldehyde
ct -Phenylpropionaldehyde
Hydratropa aldehyde
Hydratropic aldehyde
Cumene aldehyde
Hyacinthal
a-Methyl-a-toluic aldeh:

i

in

>1

cu

L

{3
0)

TJ

Ss

S

4-1
O CU

43
01
TJ
rH
CO
4J
01
O

M

0) CU
43 TJ

12
fl-S

thyl-b-o
taldehyd

benzene
acid

&>

C3 CU
4) TJ

8

CU 0)
43 TJ

CO

0) oi

rH O

rH rH

a ffi

s o

Ss-iH

>.

s

iH 4-
3 01

5 CO

Q rS

gS

43 W

4J Ol

0)
N

C3

T *

t-. o

fn CO

CU U

f *

CU
PQ

a

co"

8

8

CTi

CO

7

00
1

00

CN

vO

00

CO

P^"

1

|

1

1

CN
CN

S

CN

CTi

vO

i I
cN

S

-H

^

ON

in

319

CO O

" iH

*

T3

l-i -H CU

CO M

bo co

H

OJ C C

G 01

G H CU

U .

rH Cfl H

iH TJ

H O CO

CO (0 CO

O) 60 O

CO

to Xi O

*> 0) H

O h H

OI 01

O O rH

CU B O CO

O O TJ

l-i 00

e-

> O 3

4J 3 t-l O

Cd O)

o

3

CO rH rH

cd VM o -H

U

* 1 I

^^

-H CO rH

rJ IN! N B

OJ 4J ..

CO 3

B rH

TJ

*4H O)
U O

4J CU C 0)
H Q. 0) X

O 0) M

3 rH

G

-H

C Xi U

XI X 01

M 0)

cd

CO U 0)

o

3 4J W

<u cd

TJ H U

>-l C CO

*

01

rX B O

B -U TJ -H

r** *rH

00 )-l

4-1

TJ O CO

cd cu -H x;

- CO TJ

01 O

cd

x: o a

0) 01

X 4-1

M ed *

CU 4-1 Cfl tfl

"O B

>, to C

3 CO

TJ

O CO

4J G h
to P~i U M

X! 4J 0)

CU

XI

2 -H

4J CO -H Q

0) C 4J

ft ^J

01 CO CO

CU 4J

TJ Cfl G
H TJ -H
CO H

CO 3

rH 4J
H X

1

4-1 CU
CO CO P
r-l CU

o cd o
co co c x:

TJ G a

4J X 4-t

H

o

TJ

0) C -H

CU O 4-1

rH

OI 3 CO

CO 3 O

H ''I 3
Cg W | E

G CO

*
CO 4J
4J C
CO 01

01

H
4J

U

4-1

eM-l rH
M -r4
OI OJ O
4-1 fr.

O O O
rH CX4-I rH

3 B O cd
i 1 O O

O >>

4-1 >

CO

G H

i 1 O CU H

4-1 M TJ
CU
01 XI
4J Xl CO

rH

u o

O CO

TJ

CO

0)

3

H O
CO 4-<
rH rH
CO fO 4J

01 t"l 4J

U M 3 3

C 4J CU

-H O U

3 3 -H

*>

*

4-)

-H d

Cfl l-i Cd (0

u

0)

4J -i Cd
H U

4J tl

G 01
CU X!

CO

CU

t>

O

cd

4H

H M OJ

01 >
4J rH

M o 4-1 a

(U > 3 C
X! cd G cfl

co

CO CO S

Xl rJ (U

> 4J
rH CO

H
4-1

g

62 o
CO

U rH ffl JO

cu 4-1 g a.

3 o x:

O OJ

CO

[rt

CO 4J O

CO rH

>

s

1

CU >>

c x:

cu

CU 4J

f> O

rH 0)

CU

^^

c

i x:

XI -H

(U

oj

rH CU

4J rJ

T3

X

>.TJ

01 4J

(1) >t

o

X! rH

1

*o c

CO

H

4J CO

rH en

l^\ O

rQ

^

OI 4-J

>-,

X! TJ

5s

4->

a cu

Sen

CU H
TJ crj

rH 4J

1

XI
CU

1
m

ft

H U
t-i co

4J 1

.

O -H

4-1 |

9)

rH

oj cd oi

H

cn

!>.

n

Synonyms

p-Tolylacetaldehyd
j>-Methylphenylacet
(4-Me thylphenyl) ac

(j>-Isopropylphenyl
acetaldehyde
Cortexal

j>-Cymene-7-carboxa

2,4,6-Trimethyl-l,
^-Acetaldehyde

Chloral
Anhydrous chloral
Trlchloroethanal

(l,3-Dihydro-l,3,3-
2H-indol-2-ylidene
Fisher's aldehyde
l,3,3-Trimethyl-2-i
indollne
2-(Formylmethylene^
indollne

Benzenecarbonal
Benzenecarboxaldeh;
Benzoic aldehyde
Phenylmethanal
Artificial almond <
Benzaldehyde FFC
Phenylform aldehyde

OJ

s~*

G

eu

OJ

T3

N

^.

0)

4J

G

x:

O

01
Xi

3

X!

i

TJ

U

r7

d

01
n

< i,

Continued
Name of Compoun

(ACETALDEHYDE -

4-Me thyl benze ne
acetaldehyde

4-(L-Methylethy
acetaldehyde

Paraldehyde
(trimer of acet

Trichloroacetall

1,3,3-Trimethyl-
(2,a)-indolin
acetaldehyde

BENZALDEHYDE

OJ K
1 0)

vO

i

o
i

i

1

?

^

<j Xi

i

01

CM
0\

en
sO

1

00

1

cn

00

CM

M r|

'

1

l

1

1

|

T^

"i

cn

L/*J

si-

o

M OT

o

i

en

CM

i i

rx

oo

Fi ^J

320

i

o

c

H

1

o

c

H

i

01

a oi
>, C

JZ -H

rH
r-4 !>.

Is

O 0)

dime thy:

0) 0)

g

iu

01 1

Q 5

n\

-a -d

o-Chlorobenzaldehyde

j)-Chlorobenzaldehyde

4-((2-Chloroethyl)ethyla
o-tolualdehyde

-((2-Chloroethyl)methy]
benzaldehyde

l
1

1

p-(Diethylainino)benzald
p-Formyl-N ,N-diethylani

1

Veratraldehyde
3,4-Dinethoxybenzenecat

Protocatechualdehyde dd

ether
Protocatechuic aldehydi

ether
Vanillin methyl ether
Veratric aldehyde

Veratral
Veratryl aldehyde
Methyl vanillin

p-tert-Butylbenzaldehy
"4-tert-Butylbenzaldehy

0)

01

i i

i

i-H

1

01

-d

">,

rH rH

>^

rH

g|

js 1

fi

JL^

> cd

42

p

jC

i

0)

01

H

.fl N

4J

d

-rj

0)

-d

i

4J C

01 01

01 0)

j3 -d^

4-1 01

oi -d
S >,

01

rH
rrl

0)

rH

cd

N

i-H

cd

N

4J

01

j-

I-H rH

rH J2

^^ rC

w

'^

ri

d

^j

Chlorobenzaldel

Chlorobenzalde]

((2-Chloroethy
amino)-2-methy
dehyde

((2-Chloroethy
amino)benzalde

-((2-Cyanoethyl
amino)benzalde

, b-Uichlorobenz

-(Diethylamino>
aldehyde

,5-Dimethoxybei

,4-Uimethoxybei

rn

S G

1 (1

1 t"

M C

rH C

i

i

i

i

i

CM

sr

CM

co

CM

^r

"*

m

i

^

m

CO

m

1

03

l

|

T

1

l

CO

i

o

l

l

i i

00

CM

;*

ON

X>

i

n

CM

CO

CM
|

T*

1

1

o\

i

CM

l

<r

1

CO

O
cvl

S

O
CM

li

-O

o

er*

c^

CT>

i-H

321

cu

d

3
H

^i

H -d

T3

CO

-H

O

U CU

Ol CO CU

F-l

cu

cd u
cd

CO

cd cd

cd cd cd

>,

^

o

d

d

^

CO Pl

PI e PI

j3

i-l U

H

H

f-l

o o o

y

01

P! -H

u

U

a

a 4-1

W <W M-l

01

o c

<4-l O

cd

cd

cd

1-3

5^^

cu
d
>,

N

c

CO

d

H 0" <*
3 -d H
CO >> 3

o

H

G

T-t

P!

a

C

d co
I
CO CM

CO CO D)
CU CU
Pi C CU

cu

01

x: u

H X! CO

O

O

1

cu cu 'd

d

x; -d

cu >-.

CO

d
H

X)
X

o

Ol 01
"O XI

rH 4J

cd a>

d 0) -H
CU T) -d
CHI

01 Cj) ^

01 M-* 01

d H -d

>, 3 >.
X! CD X!

(0

M-l
CO

CU <U
TJ T>
>, >^

-P! x:

SS

Q) 0) Q)
-Q XJ T3

Synonyms^

jr-Ethoxybenzald
Ethoxybenzaldeh

Bourbonal
Ethavan
Ethovan
Ethylvanillin
Vanillal

Vanirom
Ethylprotal
Quantrovanil
Protocatechuic

4-hydroxy-3-eth

4-Ethoxy-m-aru.s
Vanillin ethyl

4-Formyl-m-benz
2,4-Disulfobenz
Benzaldehyde-2 ,

2-Sulfobenzalde
o-Formyl benzene
o-Sulfobenzalde

CO

01
N

Pi
01
XI
H
>,

g

Ct,

1.1

sodium salt
Benzaldehyde-o-
salt

2-Sulfobenzalde
Sodium benzalde

Sodium 2-formyl
Sodium o-formyl
Sodium o-benzal

^^

o

u

d

l

H

C

"c

4J CO

CO

o

C -d

l

i

ti

cS J?

x

0)

N -d

H

H

rH

"S

. -S

g

1

C H

cu u

CO
CO

CO
0)

cd

CO

3

H

d cu

4J CO

xi cd

P!

O

[d cd

^"1 ^3

CO TJ

|

CO

Q)

ri

a

Q y

XI >,

B r^

CO O

N

N

3

*cl 5

fc B

i x:

i x:

-H

Pi

Pi

H

U CJ

cu

W rQ

* cu

CO CO

1 -d

-H Pi
1 O

CO
XI

-d

O

C 14-1

H
4J

1 1

N X!

xl

O N

x: a

E3"3
G co

H

gs

g

3

a si

Z 4J

4J 0)

4J CO

O i-l

O

O

o

T* S

o 1

Cd Cd

Cd f

Cd XI

ta -d

h cd
1

1

cd

^J 1Z

^ -<r

CO

st

"*

CM

CM

oi M

o

^.

CM

CO

vO

<J XI

CM

i

CM

1

m

7

CTi

1

1
CM

00

CO

CM

fO

CM

1

1

1

1

Zj 5S

H

i I

o

CO

I

00

S9 <2

*s <

o

CM

-H

CM

CO

0>

O

H

322

.. e

&T!

4-1 Cd 4->

co s a

H 3 cd
O 00

OH rH

x: a cd

o 4-1 9 u

O UH -H

al

co >s D

O H M 0)

H co ed O

4J CU iH Cd

J*. X! rH B

rH 4J H fi

iUl -S

<J CO Cd OH

01

1

U CU
CU 0) TJ
C X! rH

cu 4J cd

NO) N

d ri

CU <H Q)
Xt > XI
> X! >,

cu

^

x:
cu

TJ
r-H
CU (U Cd rH
O TJ N O

cu

TJ

X 4-t X

>. ^ Pi C

^

cu

cu

01

O CU O

x: x: cu cu

XJ

TJ

a

TJ

eu cu xi xi

cu

^S,

^\

TJ *H "t3

TJ TJ r^\ (X

TJ

x; QJ

Xi

X!

>^ "t3 ^s

rH rH pS r*^

H

cu n

cu

cu cu

x: i cu x:

cfl (d o X

cd

*^J r^

TJ

TJ TJ

1 10 TJ CU 1

CO rH IH rH O

CO rH

CU rH X
TJ Cd CU rH -H

73 rH rH

cd rH x:

1 en CU XJ >% 1

H >-, T3 O X!
ti >, 4J

3 S

> N TJ O O

x: a -H e e
cu cu cd cu cu

N O O
fi C C
cu cu cu

y o a)

e a -o

<U CU rH

>, TJ CU X! f">

X cu !>^TJ cu X
O TJ X! H T3 O

CO -H Xi g

si"^ -M cd r

cd cd
L -H
fX) ed CJ

TJ XI X! X!

H >i in o cx ex

cd X CO ,H H -H

rH O rH rH >, >,

Xi X! X!

>s a. a

8 *

X> X! ed

&.5-S

o >, cu

x! H >, cu cd rH x:

4J cd xi T3 ed 4J

OJ C CU rH O r-H 0)

B TJ cd -H >. I

r Cfl I 3 C CM

^.T^^r^rH

O O O 5s H !>i

b a "

X rH rH

O rS H

rS h >> >, B E

O TJ U C C
H >, H H O O

rH 33 H rH EH fcj

cd I cd cd I i
co o co en o CM

.s e s

> o o

53 h fe

klfelA

H S XI
TJ C >,

^fi

JX|fX|rX|

H XI rH t)0 M 00 3

Q H ed C d C O
1 ed rH -H -H iH 1
m cj H H JH H m
cd >, lx >,
en o w co w en

H X! X! B -H S

TJ w 4J C a C
>> eu dj o cfl o

x ^ ap c., > c^
N en en vo o|\o

Mac

TJ C Cd
>^ >
P3 Cu

1 1 CO

en IA M

fe "

X

cu eu cu o <u

TJ T3 TJ X! I

t ^ a ^ s

cu eu a) S o o

T> TJ T3 H X! X!

rH r-j rH TJ 4J 4J

CQ cd Cd I CU <U QJ CU

g Nyu-lTJ BT3 H

cu cuojcnx! cnx! -^

X) XI XI I CU I CU I CU

MS 1 S* ? _i o ^ *?

^_ ?s W ?s rn PS rn ri fT*

O OOOed Oed OX!

fn ^MMN >-i N MCU

TJ -anflTJC TJG TJT>

f aaMx. axi a

-n si- -* CM en

CO sfr Q en 00

I ill I

CM en co o en

O 00 O 9^ "1

I I T i i

O O f) -f 33

cj\ o CM en sr

323

CO

cu

3

Perfumes; flavoring, pharmaceuticals,

ybenzaldehyde laboratory reagent, source 0* L. aopa

ybenzaldehyde
phenol
dehyde
phenol

Intermediate
yde

rboxaldehyde

cu
o

Perfumery, Intermediate for ant i hist amines
electroplating, flavoring
yde

CU

13

X X rH rH >,

jr

CO

Ji

X!

^*

O CU O >. cfl X

cu

cu

o

cu

CU CU

x;

0)

j-i 13 x: e co o

O X 4J H iH JC

o

rH

T3
5s

S

-a

rH

13 13

rH >, 0)

cu

T3
>i

HI
TJ CU

CU

CO

5

S

% rH

>k X! CU 0) O C 4-1

x: cu i3 e MH cd cu
1 "0 > L, 1 L,
< H x: B -* S i

1 Crf CU II 1 -N

>. 13 >>>>> 1

X rH X >? X rH

o IH cd o o o >,

X!rHrHCr4X!l-lS

Lsaldehyde
:hoxybenza

Lsic aldeh
.saldehyde

ihoxybenze

.saldehyde
:hoxybenza

cu <o -ti cu >(
TO N cu -a o

>, C 13 S*. CO

x: cu H x; -H
cu xi cd cu c
13 cu >-> -a co

rH C X CU O rH rH
CO -H O C iH Cd >>

wtm-C-Hcocosei

Lualdehyde
thylbenzal

Si

cu

i-H

cd

CJ

TH

3

Luylaldehy
Lylaldehyd
Lualdehyde

rmyltoluen

c
c

c

K

i-H
H

C
1 co

>

4J rH rH fH tj JJ T3 W

^^^ g^^^

1 CO Cd H | I | |

"o ? > -J O.|CM st <r

n *J

C aj
0|0|

n -n

c a

i T

T

III,

1 U 1 31 1 f Xi

o cu
t|?

5
',

?f V

O| O CM

r o

-M

1

13 0)

cu

CU

cu

4-) Xi

13

cu

C >i

^

>^

13

X

J2

rj

x:

CU

CU

cu

x:

j x:

13

13

-o

cu

C

si i

3 CU

rH
CO

a

rH

cd

13
H

i

3 W B

x a i

3

N

C

N

CO
N

tJ 1

CU

cu

cu

C

<U c

3 33 *?

cu

X)

D c.

J M >.

13

^

^

J^

l *

a x

H hJ

X

g

X

o

rH

H <

3 <J l-i

cu

,J

x;

x:

JS

U

PO "rj

U

U

4J

4J

C <

I) Z >i

CU

(U

Q

3 a] M

co

y

jri

S

5 5

3 eg i

5 -^ -*

CSJ

*

1
sf

i

N

CN

i

-l LO

l^

i

m

^f

1

U 1

1

1

1

^3 p

CN

Hi

i

H

3 pr

cn

,M^

*q

3 i

l

|

I

. *i *

z ->

LO

CO

S

cn

^

N

CN

|TJ c.

n

r-i

^n

rH

iTl

324

Perfumes, pharmaceutical and dyestuff
intermediate, flavoring agent

de Perfumery, flavoring
de

r clohexane-l-

mtyl)cyclo-
ihyde

Synthesis of dyes, pharmaceuticals, surface
active agents, vapor phase corrosion in-
hibitor; antioxidant for chlorophyll, mos-
quito repellent

CU

OJ

x:

?- cu w

o 5- -o

m-Tolualdehyde
m-Me thylbenzaldehydl
3-Formyltoluene

jj-Tolualdehyde
-Methylbenzaldehyd
j>-Tolylaldehyde
-Toluyl aldehyde
p_-Formyl toluene
4-Tolualdehyde

j>-Isopropylbenzalde
4-Isopropylbenzalde
p-Cuminaldehyde
Cumaldehyde
Cumic aldehyde
Cuminal

Cuminic aldehyde
Cuminyl aldehyde

1 -Me thyl-4-i sohexyl
carboxaldehyde
1 -Me thy 1-4 (4-methy]
hexane-1 -car boxa]

m-Nitrobenzaldehyde

0)

i

tj

cu

cu

N

e

i J?

TJ

TJ

0)

rH 01

cu

>,

^

Xi

&

*2.

x;

X!

cu

^

(U CO

,a

T)

p^

x: N

cu

^i

r*

O C

13

cd

cd

U

CO 0)

rH

CU

rH XI

c

S

rH

1

N

cu

Xl

CU

43

>*. CU

xi -a

t 3

rH >>

C
CU
Xl

^1

T!

CU Xi

O

F

fj

S u

x: cd

M

u

4-)

T -v

4J M

4-1

0>

0)

rH H

QJ

^1

T

CO

a

*^-/ cd

-

\

*n

1

?

CM

H

?

c^

n

CTi

FH

CM

30

o

f"^

1

A

1

I

CM

-H

1

ON

CM

CM

C*l

O\

rH

<

^

TJ

>.

0)

ff. >.

cu x:

T3 CU
H T3

rH d

CM

vO

325

W

rJ

a I
d

o
ex

Medicine, perfumery, suntan prepar-
ations, mosquito repellent, labora-
tory reagent, flavoring

cu

1

cu

T3

thylene

methylene

cu
a
>.

cu

13

Manufacture of rubber accelerators,
synthetic resins, solvents, plasti-
cizers

Antiviral properties
de

r-|

cu

r-l

Sn

cu

cd

a

(U

cd

cu

JS

TJ

d

<u

*

S

r-t
O

cu

T3

Q>

CO

(U
,0

g,

-d
cu

cu

J2

X

O

13

TJ

cu

^

CU

<^

j:

T>

>>

H

J-l

r^t Q)

o

r{

a

>^

(U

r-l

iX

TJ

>i

0) J= C
T3 OJ <U
>i 'O N

>.
cu

8

O

rS

cu cu

0)

X

o

H

a

cd

d

O
H
T3

O

N

d

cu cu

^g

.C r-l

"O

jO

-a T3

cu >,

13

cu

cu

T3 CU T3 CU

cu cd cu

i (

n

rS r-l

"a ji

0)

o

J3

p^

CU > T) >. T3

4J

X) J3

H r-l

ed -H >%

cd

N

c

cd
o

.c cd

CU N

T3 d

>, cu
s: TJ

CU r-l

d rH

H
CU 3

d d js

&
O

CU
iH

en

CU T3 JC >>i >i CU

-a >i cu jc cu ri T3

>> CUJ3T3 CUTICU >%

cu

f

"^ "id C

rC JS

4J U M-t

JS X -H
& PL, Q

cu

JO

*

E

1

Q)

s

rH 0)
d -D
.H iH

ed >%

j= a

4J f5

T cd

iH r-| l-l

cd erf >
c C d
ooo

H >^

o w

iJaS
o O

H -r-l U

a P. a>

O O 4J

M rJ ed

U 4J U

ooo

r4

a

M^,
0) -H C
ft Q i

JC
CU

d -H

J ^

-H

1

/d *O gj i I Tj p.. j -^ ^
CU >T3Cd rHCdr-lp-ICU

T3 ,c ri co cd ed ~o

H CUCdlHr-lr40r-ldr-l

cfl T3 >,cdr>>,-H>cdcd

f

-edS
g J

(U 0) 1
ti l-i <f

o

CU

C1J 0) CU

p i p ^.

H 1

. J -te

H -H 4J

Hnl O

rb f 1 4

U 1 C

rf r*^

o

?^ cd cd r*** 3 ^* 3 ^i ^*i 3 cd

CU (U

E-l El *H

1

1

1 *

H -H -H

P-i PL, ?LI

r^ *^

-1i "
u en

r^ W

CU CU M

dl ""3" Jl

en

M

1

m

3333131 331 3

(U 1

^A <y^

1

X

i

O

in

"2

1

cd

Jj

.

o

O >^

O

H

S m

T)

O U

o

CU

M Q

C (U

CM

CU T)

O 3

N rS

N ><

^i Cd

d r n

i

X d

CU 0)

W g

^

o cd

1 H

1 ^

<3

w ^

-3 cd

n u

E-

M -f

*

*

1

i i

""*

cq

00

so

en

l

T

1

1

r*^

rx

CM

oo

(N

in

r^

1^

l

t

1

en

o

en

CM

CN
vO

^J

CM

vO

326

CO

-H

CO CO

rH 01

CO t-i

CJ

H O

4-) -H

3 4J

ai 01
o j=

CO 4J

<d to

a -

CO

-i
w o

01 l-i

X! 01

-U <-H

C 0)

>, CJ

en u

cd
o

H Vj

C QJ

co -a

DO JQ

13

1

CO

01

-a

H

CO

00

C

00

o

r4

C

CO

C

H

H

CU

H

H

S

00

rH

CO

^

p*

rH

>>l

M

CO

4J

3

O

T3

o

^4

P[

>4H

Id

4-1

CO

ff

O)

CO

CO

CO

l^

CU

rH

O)

00

0)

CU

O

l_{

3

g

rH

n

CO

CO

CU

f^

*i

CU

^

4-)

4J

-d

rH

U

4

A

01

C

O

U

rt)

4J

u

H

M

a

CO

H

a

CO

^4

CO

3

01

cu

CU

o

^1

l4-{

01

>,

H

CU

f-l

rH

CO

A

T)

4J

43

01

O

o

CO

(U

43

a

CO

3

H
CO

00

4J

M

%

>

H

01

C

C

CO

f3

rH

4^4

H

p^

<4-l

M

O

CU

4J

4-1

CO

O

CU

H

o

Cfl

cd

4-1

4-1

>,

H

l

CO
H

CO
H

CO

4J

o

CO

a

4J

C

ff

CO

CO

O

CO

H

CU

01

rH

H

4_>

^

4J

M

m

CO
01

C
CO

1

CO

H

O

C

01

0)

00

TJ

co

CO

>,

00

V4

3

CO

co

H

C/3

CO

o

4J

o

CO

b

< CO

CO M

rH O

CO 4J

U CO

H M

4J 0)

3 rH

01 01

O U

cfl O

g CO

(0 M

0> CO

a. a>
1-1

H W

Vi CU

O J3

> W

CO C

rH S

b CO

01

-o

01 43

QJ "O CU

i "O ** 'O

>%-C rH

43 01 CO

at TS 01

T3 rH O C

rH CO iH Cfl

Cd rJ M 4J

4-1 >, >, C

CD 4J 4J 0)

CJ 3 3 P.

Cd 43 43 H

r-H rH rH >1

M ai w

I H I

CN a a

d

X O

^D

r4 rH

T3 -H CO

33 T3 01

1 -H O
CO. < <

01 01

T) r*l r>%

01 tS43 4=
d 43 0) 01

"S H

id cd

cd CO

rH rH H 4J O O

cfl cd cd CU -H -H ol

t-l C H O H rJ C

>, co > cd Pi >-, cd

4J -U 4J i-H 4J 4J 4-1

_ = 3^= 3 3

,0 .0 X)

>,

42

fS 01 >S >-,
J= -H ft -C
4J P^ 4J 4J

01
T3

01

co cd

r-l

at

T3

01 *
T3 I

cd cd cd
{3 H G
cfl > id

4J 4J 4-1

333
43 43 -Q
CO rH rH rH

s a s CM

01 Ol O 4J >i >> >>

rH rH rH fl 43 43 43

Cfl CO CO 0) 4J 4J 4J

> > > (X QJ QJ CL1

O O O O S S S

co co co co I I I

rH i-t rH H en. en CN

33

en

d

a

CO
4J

43

I

<u

.

CN

I rH

rH CO
>, C

-C CO

4J 4J

OJ 3

f -

I

^
m

vT

CN

327

I (d co

^ u oi

73 Cfl tH T3

d a^H -H

CO Ol iH O

fc b H

rH O. 3 4J

o a. cj

43

01

- CO

u d ca d

rH Ol >H -H

(0 > O

H 4J *

rH O Cd CO

>, CO tl r-H

4J CU

XI -H 01

u

CJ

cfl
IH O

o

d .
t-t n

IH
CU
43

I I XI
d 01 3

> T3 rJ

CO

H -

O O CO

H JS d

d o -H
cd o ca

00 <-H CU
IH CO l-i

o

<4H
00 O
_|j C
d iH Ol

01 d M

rH IH CO

cd oi cj

JQ H

rH 43 U

>i 3 Xt

X IH 3

CU rH

cu H O m

e>< o
43 d

oi 4J o d

01 -H O

i t! *

Cd 4-1

4J O

cd

J-l tH

H CU

(3 43

rJ 4J

cd cd

3 CU

rH
CO

cd

CO
H
M CO

cd cu

01 43
4J 4J

C

cd co

S 4J

d

> CO

C -H

cd x

M O

cd d
ti cd

CO O

5

3 CO

IW -H

IH -H
CU Ol

a d

O

(X IH
cd U
O -H
C/J O

0)

C
H
4-J

o
o

<N

I

w

1

o

a

4-1

d

a
\

CU

I

CU

Ps HO)
43 CU cd rH
01 73 d O

a ts a) M

rH 43 4-1 U

cd cu 3 cd

CO Cd -H CO CN PS

d d d rH i 42

o o o ?s w 4-1

4J 4J OJ 4-1 d CU

o o o o co 2

IH *H M rJ M I

O O cj cj 4-1 en

o
o

T3

1

^,

.-n

1 43

CU

<]

x cu

T3

r

o -a

^^

CU

X-N

43 -H

43

73

rH

IH cd

CU

^^

^j

Cd N

73

43 0)

4J

ehyde
butenal

-a

cu H d

73 cd CU

tS C 4J

hexanec
ydroben

i-H
Cd 01
N 73

01 43
43 0) 01
O 73 d

exene
boxalde
aldehyd

d a)

5-1

C ^3
4J H

*o l

43 CU O

O 43

r4 rH 0)

43 H N

o) cd

H CM
cd 1

CU 4J O

01 T) 3 1

TJ S

X 1 01

o cd d

H U 01

P S

T3 i-H 43 sO

>, CU

43 rH 43

U 1 43

v* 01

O $*i

!*. cd I 1

O 43

cd | o

> st O

1 43

0) 43 CM r-H

rH iH

t-l d rH

O 1 M

>-, O

o w

T3 0) T3 1 tr,

4J 01 CJ

1 CU 73

X IH

>> T3 -H H H X!
X! H O >i cd -U

4J CU 4J
3 73 3

01 X >

t- 3 o

n d >

1 01 43

O 73
M >,

rH 1

0) cd Cd 43 d Ol

3Q s^ pjQ

1 43 H

H X d

73 rd

t3 *J H

1 43 t

sO O >*

>-, 0) -4

rS Cd

43 1
4-1 CO

rH CJ O -d iH

cd -H iH S O Q

4-1 01 -U
IH 73 IH

-HE
f) CJ fi

243 4J
0)

rH 1 U

CU C

jj td

i t->

rH H rH | 43 1

00 60 60CM 3 r^
H -H iH 1 1

01 rH 0)
4J CtJ 4J
| I

"IVt

H H
Cu O 1

cd <r cu

CM 4J

H EI H Cd TSjcO

* sl-

l "H *

rH CJ <

rJ *

1

T

,-x

/ _ x

1

X!

1 0)

cd

IH

/^^

H d

I

H 1

1

PS 01

H

O

43 O

^^

W QJ

cd

CO

| l prt

CJ

CU 43

d

iH

CU &i

1

Q O (U

0)

rH ^

1 1

1 "i *^

4J

T3 1

>>CJ

1

<fr U >*

3

^^/

43 W

pj

| K^ C*

43

4J !Z

2

>s U 01

1

j

S<

^q

X 1 73

CM

3

>< M

^ w a

Q 3C >H

n S

&M Q
5C ^4

<*1 H

M ^^ *0

73 rH X

^

W

1 O =C

^D 3C

> >, O

43

2

rH iJ W

J Cd

33 4J 45

4-1

O

rn" U 3

CJ Q

i d IH

rtl

^^ ^j

-a- at

s

-,

vx cj <3

CJ <

^ a, o

1

M

1

1

i

CM

CJ

en

"*

O

up

T

t

m

n

CM

CM

u-l

o

l

l

1

1

i

sO

i-H

O

^

ON

o

^

i-H

-0

I 1

O

^H

CM

m

328

00
c

-H
J-i

CO

^3

C!
CU

3?

g,

H |

J3 *H

CO O

4-1 CO

CO C

CO

C co

O rJ

H OJ

CO .Q

C H

o> m
S

H M

T3 (0

4J

CO O

JD CO
CO
IH c

co g,
co co

CU V-l

ex UH
I O

4J

C C

oi a

C iH

aj 4.)

ecO
N
0> H

Ol rH

C O

H JC. rH

CO O O

4J CJ

c rH q

o <o -H
o

H

cn E^'-x

T3 C co

(3 -H r-j

3 > c3

O P -H

-a C
3 CO

I C
H cO

(U CO
U CU

OJ CO

CO CU

(0

0) 0)
>i 4J
X

2 p

O -H
X 01

C -H

r4 3

gO CU CU rH

fti 4J CO 4-1
CJ v-' CO CO

B U 00

M U) s-/ C3

a o 1-1

m 3 i* B

O CO C rH

4J M O H <0
C 00 -H Ol J3

01 34-10
M rH H O 0)

Of >,rH ,J

X cu a. >
O O

op

C

CU

p

N

H pC CJ 00 00

rH >, H Cf

H rH CO "H rH

JQ O W N CO

3 5. CO -H S

**

w

co C
OO cU

g c?

U H

o

is. I

CO H

a

oo ca
fl o

H rH

CJ 3

<u
a

T3 CU
>-, "0

fi fH
(U ctj

ex CL

cu

CU -C
T3 01

s-g-a'i

G T3 cd

H rH rH O

tj tJ > 01
cj cj a

a
p cu -a o

CU 01
01 tl TJ

CQ 01
O $

01 cO cu
T3 "00"
H CJ -H -Q

iQJOJrH

c a a <

cu cu
to cd

cd ca

cy TJ
u

<u

!>

OJ

a

cu

"O

>,
ai

13

a,

01 X

<u

Ol 1

cu
o

d

i-H
>%
4-J

ca

H
M

^

rH
!s~,

a
cu

s

M

4-1

^

0)

*o

1

o

H

CU T)
C 0)
O (3
H Cfl

xa
xy

o o o o o
>, >, >, IM " -

iH rH rH -H
'J> O U M

c

CO
O

cu

Tl
O

a

CJ

o

3

IH

CNI

^H

cn
I

CNI

T

esi

CM
CN

7 1

329

-C

CU

1

1 1

4J

A

1

A

>

B

4J CO

*

e
o

r-l

(U

o

B

CO

fi

H

4->

rt

CO B
0) 0)

co

rH

4J ti

Q

cO

4J

cd

CO B

B

r-l -O

0)

cfl

oo

CO 01

B

4J

> -H

O

4J B

4-1

H

c

-a

rH*

H

CU

U

M

H

O

CO

)t

H

E -H

U rH

CO

CO

a.

D

a) co

CO

CO CJ

IH

4-1

CU S

ft)

p

4-1

CU

ca co

O

CO

-a

CO 4-1

J

00 CO

CO -H

01

CU

B

cu

^i

CU 01

3 3

cd
0)

O 4J

h 11

3

O (U

4J

ca

O
CO

rH* .H

g

H
CO

i-i
a. 4J

M
O

1-1 rH

a jo

x
o

B co

n

CJ

H a,

CU

^

cj cd

H

B

CJ

1 H

.0

H

>i tfl

M CO

rH

?* rJ

a

0)

CU CO

1-1

E

^

-H

j=

(U

CO 01

0)
4J

s,

rH 4-1

00 01

co oo
-O cfl

l-i

-H CO

-a o

cfl

o

^ -H
>*^ CO

1

01 >

A

CO

4J

cu

H

CU

co a

<H r-l

cfl

> H

op co

4J

A

01 CU

B

3 00

i-i

)_i

Cfl 00

^

H 00

C 4J

CU

CO

B E

H

rH B

rH

3

cu

4-1

3J

4J

H CJ

o

B

01 Q)

O

LM i-l

H

-a co

f"J

B ^"J

C

CJ O

CO

H

rH rH

H

OQ

o

4J

ai o

OJ
00

CO 4->

cd T3

e o

a

CO

ai

-C .B

23

-a

co P

O

H 4J

B cfl

B

i-i

4-1 4-1

J5

r-l CU

B

rH -O

a

u c

P a

cfl

<U CU

H M

CO

-H CO

B

cu cu

4J

P*

o

9

A

r~^

0) 4-1

cd

CU Q

C
01

3P

H I
> 1

U-l 4J

E

4-> Cfl
B 4J

OJ

1

** cd

CO X

B cu
H X

ca

0)

co

-Q 4-1
CU 0)

a

rH

00

CU

rH rH

H H

co

r-l

cfl

X 4J

01 CO

cfl

*1^ ^

o

rH

co

op

O 4J

op

01 4J

bfi

-E <-!

O

OI

01 -

^

- etf

'4-1

^

3

CO

p

4J

a a

j

Q

r-l rH

i^

/-^

O

B 01

CO

3 >

H

to H

S

C

O

cu

CU Of

H 4J

4J

T3 3

cd

T3

4J

N

"O B

>^

o

T3 E

cd

B

c

B

H -H

H

H T-I

i-l

r-l U-|

4-1

O cfl

rH

3 co

a -U

H >,
4J rH

O
H

CO

JC

rH
H

CJ B

H CU

11

4-)

B

2 S

CU

U

cO

r-l -<

cd cd

4J

01

to

0)

Q) >.

{j

E -a

o

CJ

H 4J

-Q E

O
H

I-i
Li QJ

U

0>

4J ,_(

U

Ul

(U

cu cd

CU

H 01

4-1

o u

<3

CJ (-1

CO U

CO

ZJ

D. ai

14-1

M-B

rB S

o

<4-4 CO

C

01

- 00

co cd

4J

co c

4J -H

CJ W-l

OI O

4-1 O

C i-l

H a
ji P

H 01
T3 4J

.5

CO
0) -O

-o c

H Cfl

o

H M

>w 01

OI

U 01

O -O

CO M

XI cfl

CO

CU CO 4J

TJ 0) TJ

H > rH

U -H Q)

H Cfl 00
SO OI

C J= M
3-00

JU Cfl U-l

01
JC

O
U "

H O
C

CO

oo en

H 3

O O

CU

I

15
-o

0> 01

TJ -a

>MH

J2 X
01 O

H 01

rH B

rH CJ rH rH
CO -H tO O

e SE

CO

C r-t
CCJ >>

CU
T3

UIT-1^--" (-1 pO*J VJ

-H CJ4J4J o t -W -H E
r^-HCUOI-HUQCOO

O O

4-1 S

CO I

r-l O

Ji rH 4J

OI O CU

CU "^ S &

B rH W ?

. cfl CO O X

. . O X fl *w O

S H H O W -H H

>J M M h O r ri ^l

W co|E-i H H Cu E- H

CU

1

CU

-a

rH

cd
B B

H O

X >4-l

O cd

H 4J

f-l 0)

E- S

T)
(U

H
U

a
o

o

a

I

CJ

z

w

X
o
H
i-i

m

CM

Jl

W

H

<

4

in

o

o
o

oo

A

IN

m
o

330

i

01
CJ

cd
co oi

r-H CO

cd o

(4-1
O

01 rH

4J rH

at a)

B CJ

O *

H CU

d CO

cd o

60 rH

U 3

rH

Jj 0)

01 U

j= o

j^l ll

O AJ

o
I 1-1

Cd -H

rH O

4J d

Ol Ol

a

IH

o

01 -C

4J O

cd u

T* rH

a cd
oi

Ol rH

r*

CO

d(U T3
>> d
d -a cd

co o oi d

o cd

JS rH

0) 0)

d >

01 rH

H O d >
T3 CO W J3

4J 4J CO

d

oi _. _

0)

cd

B

.5.2!

cd

d xi
oi

cd

d co

H -H
4J 01
4-1 Ol

2i

01

CO >

l-l -H

01 CO

S cd

, rH
rH A

o d
o.

d "o
cd

J-l 01
3 r-l

T3 CJ

d cd
cd 4-1

0)

tf h

CJ O 3 "

H .H Ol 4J d

a 4J n o o

H a cd ed -r-i

T3 3 r-i 4-1 4J

Cd r-l 3 Cd

4J 4-1 d N

'" CO O Cd H

oi d B d

o O 60

H o d u

CJ i-l OOrH

H ti d d 3

60 Cd H iH >

d O "-I rH

3 U OJ O 00

^ ... ^ Cd H

J rH oi 4-i ed

Ol rH d rH

rH ,J H 01

rH 4J CO CO rH

,_i ^i >,rH a;

^ d rH Cd CJ

O 4J CJ

73 CX 4-1 01 Cd

ai -r-i o a

01 T3 "

3 cd d T3 rd

o d co

T3 -H Cd -H

co d *J d

60 Cd O M rH

d 3 43 cd

^ -O T) 4J >

d Tl O rH

1-1 O rH Cd 4-1

r-l Cfl CX 0) O

4-1 Cd

d oi

d d
H cd

4J 3

01
60 4H

cd o

01

rH CO

H

. CO
(U 01

P

H rS

e co

QJ

60 >^

4-1

O> CO

T3 -H

H a

U 0)

H ^:

4J U

I oo

01 C

H

C

td CQ

H Oi
CQ ^
O -H

CO
O O
H
4-)

rH 3

oi

d t)
cd cd
u 6

PL. f-t

01 cd

M J=
I O.

O l-i
4)

4J r-l

O Ol

cd o.
14-1

3

d co

0)

R
s

313
g y

Pn

I

01

s

XJ
01

T3 0)

rH -I

cd o

l-i IH CU 01

. 3 3 -H rH

(4_| l|-| 14-1 O Cd

H M rH h rH

=J 3 3 3 3

rH =

,0 cd cJ

cdrHcd>ca

Cdd

-Hd>,33

iw >,

-

>.0l
H T3

01
0,1

R^

^ -d
01 <a
n

01

a

a> >^ a>

Tj rd T3

O) >i Ol >i

-O ji T3 J3

>% CU rH 01

OJ JS T3 "O

^jrH CJrH <U--J'-I:

edcd^o > ort>% c 5

43jd-Cj3rH4J*-t C
4J4J4J4J Cd CX CX Cd

d d

al

^ d d
cd cd cj tB

pt
He
He

cd Q

- J3 rtf

e 4J 4J

ed d d

+j cd d

CM Cb tn ft, fc, tti

lill.siaifci.al'ls

Oenanthole
Oenanthic aldel

R

^7

T3 CJ

rH

cd cu

J2 13
4J >,

s-s

d t)

01 H

o -^

I
o

OO

331

CO

H
CO
01
J-l

co y

D 4-1
N 01
H JS

y 4-i
2 g,

CO CO

co

rH "

O. CO

0)

> 73

CO

H CO

CO rH

CO CO

x: y

U -H CO

c a <u

^ 01 73

co

y y

U H

H l-l 4J

d cu y

CO -Q CO

,
3 e

cu

01

cu cu

,=

">! f

r-|

w

x: st

cd

*^

01 1

1

CO

73 rH

C3.

i-H

X

r "j p

73 CU

d

o

4J

> H CU

0)

1^

rH CU

-d O 73

CH

>> P

Synonyms

a-Pentylcinnamalde
a-Arayl-3-phenylacr
a -Amyl cinnamaldehy
Amyl c i nn amald e hy de
Flomine
Jasnunaldehyde

2 , 6-Dimethyl-5-hep

Sorbaldehyde
Sorbic aldehyde
1 ,3-Pentadiene-l-c<
2,4-Hexadien-l-al

CO
73
Qj >. rH

T3 CO j=! H co -
> CU 73 Qi co d
.C 73 X 73 d S

73 11 . J3 rH CU I <

>%73^CU <U CO XCM,

s -^ -p s i <

aJCd73rHrH>, (J XX3
T3 H Cd Cfl J3 ^ | CU

rHyrdodcu d CMS^

CO H d p CO 73 D l|
OOOQ-XrH rH COCOC

M t-i j-i cd <u co >, ddi
aaaosx x cococ

ucS^tic^ s si:

2-trans-Hexenal
(E)-2-Hexenal
Leaf aldehyde

Isodihydro lavandul
2-Isopropylidene-5-

j^

i

> to

A C

^^

01

U O)

d

01 M

*X3

4-J

cu

S cu

C^

C

,H_|

i

o

3

^

m

1

j

-I f

a

U

i

^^

1 <-s

ntinued

o

<4H

01

PTANAL -

cu d

JS CO

-Dime thy]
EPTENAL

i i

Q
1

13

d ^3 c

^ < 01
*J 2 X

CN g

H CU

rd -H
LJ rH

o

B

Ef3

v^ / (^

\O 03

si-

5 W o)

1 J->

cO

rX<

1 CU

A

ri ^^ rplj

m co

3

^

CM ^5

CM

CM

= CM

CN

It

01
jQ

r*

ON
CM

v>
CO

T 1 co r>.
in ' '

l

w

|

st

I

CO

cs ? >0

00
CN

.1

f,

CM

CM

' 1 1

pf\

CM

o

in m

J.

2

CO

1 I

4

CO O

o

H

CJ

co in

-H

CO
CO

332

Tl

C

cd
c
o
z

Bl

c

CU 4J

D

M-l T3
)-i O
CU M
PL, a

cu

TJ

co

X cu cu

O r-l r-l

XI O O

CO C C

-H -r-l

1 r-| rH
?|-

0) 4J C

-i QJ O

o i "4-1

T3 I I

C CM CO

H I I

r-l iH -H

>-. >> >.

xJ s j=

4J EJ 4J

fff

CM CO CM

CO

d

Sir

' cu

CU

T3 CU

H
TO

H X! H rH

4J r-| 4J

jC cd j-1

ax: a,

34-1 Cd

J3 C

I a. i

^ cd a
i c

aph
tha
pht

-n
h
a
-

n cu

l-l T3

CO rH

O cd

2-Hydroxy
2-Hydroxy
2-Hydroxy

y d r oxy - 1
ydroxynap
orm-2-n

y
aphthol-i
aphthol-1

cu

TJ

cu ^

cu -d cu x:

cu T3 J^-a cu

73 f^ >l H3
CU >^ X CU -C tH

d x! eg -d a) cd

e
y
e
d
l
d

ehyd
ldeh
lald
c al

oic a
ona

g
gonic

2- H
2-H
1 -F
2-N
B-N

onald
-Nonal
-Nony
onyli
onan
elar
elar

tral
ranial
r ani al de hyd e

,
cu

-d

>,>,0.i-l

UMcdco
aau u

,

0) OJ CU

CH-U4J

a)
TJ c

>> I b

XJ J

CU
T3

- OJ S

H T> ro

, erf Ss o

4J J3 U-l

CJ CU -H

O T3

^ rf )^ ^4 f I r-n *>* M *4 l^ VAI ^^ v *^ ** 4^ %-^ ^^ *^ u *-

I I o o a) a) HOICU cdcdi oouui I I ,H f-1
d|c|zzaiPH ocju ooc|ooooa|d|c!|oi5

00

o

I

CM

en
m

333

ery (fixative, muguet odor),
ing, soap and cosmetic fragrances

Lng agent, fragrance

ng, rubber accelerators

cd

e

cd

a

CO*

c

H
CO

cu
h

CO

cu
^

TJ
Ul

o

M-l

d

4J

cd

H CO
T3 H

to

j_i

H

cu cd

CO

O

4-1 >

o

to
O

I CJ

C 1-1

cu

3

to co
Q) H
PM IH

CO

^H

f Tj

Cd
H

CU 4J
4J 3

c cu

'-*-!

M

(U

T3

>,

45

,_!

CU

cd

T3

C
cd

4J

H
CO

5 8

O

/\

H O
(U 43

CU

onyms

roxyc itronellal
-Dimethyl-7-hydroxyc
fd roxyc itronel lal
ronelial hydrate
Lalia

Losia
,1

CU CU H h

o t> o cd

>> >i to <J
<U 4= JS 1

H cu m cd CN

<i T3 T3 rH I

H r-t rH >.. flj

00 fl C C

H c s cu cu

4J -H CO CJ J= 4J

cu to a ^ a o
5 a 5 S '

* "H cd QQ. I
e qj u c i ^
> c H C H i
w -H >, ^ S;,H

S ^^^ xo>,

C 4J 4J Cd (U QJ C
3 TJ "i S{ SB 1J =3rH^S

Idaldehyde

R
s ^

H "

T3 cd C Q) 43 T3
>.CO CU T3CUCUr-|
43CO-H T3 >, T3 -Tl d

QJ a a cu >, 4= 3 >,

^Op T045 OJC043T3

THSfe ^^ " <U^

rtaa x!T3 -HOTSOrH

^5 && ^-a ^7j fl s

^|a 1 3S7j4i5 1 ii53

:hylvaleraldehyde
:hylpentanal
nnylpentane

c

^ K^ F^ 1 II \,

> - 1 H fs & !
a en r^ o rj c_j &

JJi>^33M | &-.IX!

5 S ^ s? fip" 3 ci 5? tift;

H T^ 3 3 J3 | CU 1 1
Hi-JJSS^, 83JQ-H

o

H
O

^^J^J, CUCflcUCUCUCUOJOJ

>,-Henen r-j> I _| HrHrHr j OL(
pHO,.. cO| cOcdcOcOcoi
O H CM CN > c|> > t> > > qjl

OJ ^
CN 8 CM

C

,_(

cd

ji

u

W

4J

o

Q

'"' s

cu

S

T3

-H

c

b]

a

4J tJ

0)

Q

3

C 1

H

j

H

o

O !*

?s

3

o.

U

,JM

^^

^j H

CD o

1 ? M

4J
CU

O

CQ

cO
u

fl ^
H o

<j o c

g

U

J

cu

a

H

4J

2 *a ij

cu

j2

s

>

(H CU

EH >, /j

j^

<G

2

u

o 1

S 2

Y

X

E-.

cu

CM

o

&J

1

CM

CN

1 nj
<1 J3

1

f

1

T

a.

H |

1

vO
00
1

<n

1

CM
vO

1

i

3 <

o

i

O
1

vO

r*.

o

1 1

en
CM

i

334

>, CO

W 43 Cd

U M iw
-HUG
d H ^
O 4J CO

H co -H

O. Cd T)

>
d043-H

01

Ol
T3

0)
CO TJ

01 01 01

X-O 42 43 43
(U 42 >, r-j OJ Ol Q)

>,TJOITJ CrH,-jrH

1

H <U
>>TJ

4J 43
0) CU

rH
rS 0)

3 >>

1 0)

CU
TJ

01

01

<"{

CU

TJ ts

e

TJ

4J ^}

CU TJ

TJ

01

d

0)

43

01 cd i i 43 cd cL d (3

M rH

TJ H

CU >>

TJ

o

TJ

0)

43 01 0)

TJ CO 0) d O O rH O

a

cd

u cd

ts cd

TJ 43

>> Ol

rH

cd

H
TJ

TJ
01 H

0) TJ TJ
TJ X r-l

r-JOSTJCOH-H>s.H
cd-H COrH 0.0,0,0,0,

rH

v^ CD

01 43 4J
TJ (U CU

43 TJ
CU H
TJ ed

H
TJ

CU

d
cd

0)

TJ
r-j rH

TJ Cd
5s
43

H 43 Cd

cd cu w

TJ 01

a g d CD o i o o o
dd-HOia.| 0.0.0.

3

d
d

H

HI

>, TJ O
43 H Cd
01 CO rH

rH rH -H

ed cd TJ

I-l W r4

O

d -H
cd t-<

X

0) U

TJ d

H Q)

cd cd
d d

0) -H

a d

I-) O

U H U

H cd cd

rH H rH

d d O CJrHrH'HrH'H
HiH O Cd >%^>>^>%>^

CQ
1
4J

o
o

r4 rH

rH O

b

H 43 M

TJ fs

rH 43
cd -H 4-1

cd cd cd

co cd

0)

U CU

H -H

Id -H

>. rS >.

O O TJ ^ 0) CU Q) CD Ol

M

TJ Cd

CO 4J TJ

rH rH 0)

4J 4J 4J

_g => 3

0) 4-1

a 3

a

CO

2 '

d m

a o.
o o

a a
o o

O. O.43

O O 4J

M U S^NJ342424343
TJTJ43 dPMpLiCLipLirii

0)

&-H

43 H

tsj} >,

>H S 43

cd cd S

> > H

1 ( 1 ( 1

U

33

o -

U5 rH

W M

DH en

rJ H

ex, a,

H U Q)
BU (Xi S

>^>-H QJ 1 | 1 1 1
33 33 Q DQcO-noncncQ.

CX|

H
J

-1 '

rJ 3

H H h

&H C4 H

M

O

OH

d
cd
o.
o

o.
cu

d

0)
N

d

0)

4J CU

Q) 43

a rH rH

H >. Cd

Q 43 d

I 4-1 Cd

rH 0) Q.

O

I

st

O

en

sO

oo

?

en
cs

en

I
o

m
i

335

C M O Tl

cd o > -a

T3 O CO Cd

H >-, M

X I 4-1 O"

o oo c

i-> M CO M

C >, 0" O

TJ 4J S CD

l-l 0) IH 00

oi a )-i

X) O 01 "

X) oi a co

fi - H

l-l CO CO

J-i O -H 0)

u-i co ui

01

U CO

U M C lJ

CO O >> Ol

H U CO N

O CO H

CU M O O

acU -H T-l

H c: w

0) OJ CO CO

^ O to ca

C3 O U M

i-' co o a

01 OJ

i

"^ "5

Synonyms

2 , 2-Dimethylpropionaldehyde
a,a-Dimethylpropionaldehyde
a , a -Dime thyl propanal
Neopentanal

_t-Bu tyl car boxalde hyde
_t-Butylformaldehyde

-Isopropyl-a-methylhydro-
cinnamaldehyde
Cyclamal

Cyclamen aldehyde
Aldehyde B

j>-Isopropylphenyl-ct-methyl-
propyl aldehyde
ot-Methyl--isopropylhydro-
ci nnamaldehyde

2 -Me thyl-3-(j)-isopropylphenyl )
propionaldehyde
3-(4-Isopropylphenyl)-2-nethyl
propanal

Isobutyr aide hyde
Iso but anal

Iso-butyraldehyde
2-Methylpropionaldehyde
Isopropyl aldehyde
Isopropyl formaldehyde
a-Methylpropionaldehyde
Dimethyl acetaldehyde

Methional
3-( Me thyl thio) propionaldehyde
B-(Methylthio) propionaldehyde
3-Methylthiopropionaldehyde
B-(Methylmercapto)propionaldeh>
3-(Methylraercapto)propionaldehj

1

1 M
M

b c

M

cd

T-l

T3

cd

JC to

co

CX

mpoun<

C

o

CJ

1

a
o
u
a

01 O

P a

i oi
1 CU

c

CO

a

o
a

/"x

O

0)

o
CJ

_J

4J

sr N

1 G

o

H

x:

d

M-i

2J

0) TJ

8 u

M 0)

a

M

H

-M

O

3

x: ^.

x:

a

01

H

O

1

CU P*i

J-l

m

O

o

1

V >

CM

f 5

01

01

f
CN

T

CO

CN

^

<!

^*J

XI

7"

CN

CO

4

m

1

1

W

J

ON

1

00

0\

Pg

w

3

30

r-^

00

336

(U

01" 3 ,

<H an

co c

T) 4J O
H C O H

U rH

iH O -H CO (2

T-f C

O > H 4n ed

i c

M CO J3 4J 3 00

ai eg

<u e n c e n

o -H oi 01 cd o

CJ

>, 00 rC 00 S

rH 01 CO

X n

ijQ l-i . -.03

0) C

-H -H

M fcO 4J rH
(J l-l rH P! C Id

CX >_i

H QJ Cd -H Id JJ

S J2

4J 4J O C V-l 0)

O 4->

01 CO -H M 01 6

O 0)

J2 0) 4J cd 60

4J P-v D H *W

4-1 >,

d r-t 0) l-l O

O CX

>> O "4-1

to co C

CO CX Cd tO (U CO
Q 0) t-l S

H eg H

U T3 M S M

CO l-l

O C Cd 3 (U O

01 -C
J3 U >

4H ed f IH T3 4-i

ex n -H

4-1 3 cd

C CO rH

!> m

CO CO

01 0) 0) r-l rH

4j C ex o ed

Cd CO 0) H T3

H ,c c J3 -^ en

T3 >

-O JJ -H CO U O 01

O B )-i

01 01 |2 CC] rH CO

H D QJ

cox;

i VJ O W) rH r-l (U
C 3 -H S*. O rC

ed cx u

4) >, JS JJ rC O 4-1

00 6 td

4J H W cd 4J p
C O 01 0) 0) 4-1 >>

O O rH

M 0. 4J S CD

Q>

>*,

0)
iH

i

cd

i

C

>,

c

01 01

01

O

H

1

-d -a <u

T3

> > "O

^l

<Ti

* eu

Pyruvaldehyde
Pyruvic aldehyde
Ace tyl formaldehyde
Acetylfonnyl
a-Ketopropionaldeh
2-Ketopropionaldeh
Methylglyoxal
Pyroracemic dldehy

Malonaldehyde
Malondialdehyde
Malonyldialdehyde
Malonic dialdehyde
1 , 3-Propanedione
1 ,3-Propanedialdeh

0)
T3
>t 01 <H U

O eU > 1 O

J2 H 01 1 -i
0) * 13 S 1
(3 rH 'O rH 0) 12 (^
HedrHOCdl QJS-H
OlCCCjiH CNCX*r-ICO
HOlrHrHrHI OrHOO

O CX>&-,>CXr-i ed

4-Hydroxy-3,5-dirae
cinnam aldehyde
Sinapaldehyde
Sinapic aldehyde
Sinapyl aldehyde

4-Hydroxy-3-raetho:
Coniferaldehyde
j>-Conifer aldehyde
Ferulaldehyde
Coniteryl aldehydi

i

&

O -H

i

Cd

1 H

0) CU

in >,

B a

c

1 O

en cu

en l-i

I CX

rH

r>, CX rH

>s 1

C{J

X CM

C

T

i

X C

1

cd

^j

J^

r-l O 0)

U />,

Ou

^^

^3

T3 rH

O

U

Q
U

S

>\ AJ o

35 Q) M

33 C?

CX

o
c^

CU
O

o

e

i

sir
i

1 01

v' CX
1

1

i

CM

m

en

30

o

4>

3O

i^

|

l

\

1

1
CO

CM

=0

>o

OO

en

f

O
1

m
l

en

1

1

fs^

20

00

CM

o

o

m

r>-

m

t-H

CM

^-4.

*

337

a
o
a

OJ

o

OJ 0) 42
O T3 01

42 42 rH
OJ OJ CO

H H O
(0 (0 -H

can
c c c

H -H i-l

y u y

o o o

f*S ?! r*"l ^l

42 43 42

42 42 42 42

4J 4J 4J

4J 4J *J 4J

0)0)0)
f T?

O|-M b|

Iff*
a a CM CM

I >,

(2 (2 C & N

(2 C 13 CO C

H -H -H cO CU

L> O U CO CQ

dehyde

CU >i
43

, QJ Q)
42 TJ T3

>. Q) rH >

43 T3 cfl

0)

OJ . -

O cfl CM

rH f2 I

CO -H OJ

QJ OJ

42 43
OJ Q}
13 *O

OJ

H C

(0

O

rH y

O -H

y ix,

H I

0)

c o

H ^
. rH rj
H O -H

rt

-i ...

>% O -H O

(^ ^H t" -H

CM Oi CM Cb

O
O

(2

8
!

O

s

1

&t

0)

42

a

X co

o a

42 QJ

4J a

cu o

*C n

T a

0}

c!

I OJ

rH &

fs o

42 P

u a.
^ CM

CM

rH

CO

(2
CU

a
o

M

ex

CM
I

I

CM

(0

tf

0)
CU
O

P

a
l

CM

H d

>-. CJ

U OJ

I a

m o

M

sf a

l

<r> CM

N-/ I
I

cn

(N

3 5
9 2g

O

m

CO

CO

l

co
m

30
00

m
m

o
o\
I

vO

f

o

vO

I

338

01

-a cu
>% c

JZ H
CU

dehyde

13 H

cd
X
O

-O .0
H J-i
M Cd

cd >-, o
c a. ^H

H i-H >\

W >^ T3
O 6 H
O C VH
H O >

Tt^

c

-(l-4)N,N'-bis-
l)D-streptamini

01
T3

t aldehyde
c aldehyde
ehyde
al

cu
u

Ol >%

cu
T?

H 1 r-i
?> r-1 >1

?,

J5

0! -H T3 d
CJ W rH cd

TJ J3

rS Q*

^

Streptomycin A
o-2-Deoxy-2-(meth

1-glucopyranosj
( ana no iminoraett

Sesquisulf ate
AgriStrep
Streptobrettln

Streptorex
Vetstrep

Tylosin A
Tylosine

rH
C C
O 03 O
F-H rH rH

n-Undecanal

Hendecanal
Hendecanaldehyde

Undecyl aldehyde
ri-Undecylic aide!

Methyl _n-nonyl a
Methyl nonyl ace
Methylnonylaceta
2-Methyl-l-undec
Aldehyde M.N.A.

Undecenoic aldeh
9 -Undecylene aid

Undecylenic aide

z

U

s

PH

E-
c/j

C
U

!

U

a
cu

1

<
CJ

w

01
f

OJ

NDECE

O
a\

vO

1

O

CO

en

339

340

REFERENCES

CHEMLINE Data Base. Bethesda, Md.: National Library of

Medicine, April 1980.

CHEMNAME. DIALOG Database. Palo Alto, Gal.: Lockheed

Missiles & Space Co., Inc., June 1980.

Fassett, D. W. Aldehydes and acetals, pp. 1959-1989. In

Patty, F. A., Ed. Industrial Hygiene and Toxicology. 2nd

rev. ed. D. W. Fassett and D. D. Irish, Eds. Vol. IT.

Toxicology. New York: Interscience Publishers, 1963.

Hawley, G. G. , Ed. The Condensed Chemical Dictionary. 9th

ed. New York: Van Nostrand Reinhardt, 1977.

Weast, R. C. , and M. J. Astle, Eds. Handbook of Chemistry

and Physics. 59th Edition. 1978-1979. Cleveland, Ohio:

The Chemical Rubber Co., 1978.

Windholz, M. , S. Budavari, L. Y. Stroumtsos, and

M. N. Fertig, Eds. The Merck Index. An Encyclopedia of

Chemicals and Drugs. 9th ed. Rahway, N. J. : Merck & Co.,

Inc., 1976.